1975 SRV 220 Overnighter Hard Top - Anybody know the Top Speed?

mitchvon

New Member
Sep 2, 2023
12
Port Angeles, WA.
Boat Info
1975 Sea Ray SRV220 Overnighter HD, EZ Loader dual axle trailer Boat was garage find only 535hrs
Engines
1 engine OMC/Ford 302 V8 with a 2 barrel carb
Greetings. I receintly purchased a 1975 SRV 220 Overnighter Hardtop with only 532 hrs. Does anybody know what the tops speed of this vessel? The boat had been stored in a garage for years. I drained the tank and cleaned the fuel lines. Put fresh non-ethanol gas in her and got it running. I took her out on the water on a calm day but could only reach a top speed of 20kts. The engins is a 302V8 the valve cover shows 188 and I'm guessing that is the HP. I've owned wooden Chris Crafts in the past but looking forward time with the Sea Ray. Any help wuld be appreacited.
 

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We had that engine in n 18ft srv, could get it a tad over 50 on the GPS (ha, no GPS in those days, who knows how accurate the speedo was).

That likely was the base engine in that boat, most would have come with the 228hp (351cuin). I'm guessing about 30-35 mph as that boat would weigh twice what our 18' boat weighed.
 
Greetings. I receintly purchased a 1975 SRV 220 Overnighter Hardtop with only 532 hrs. Does anybody know what the tops speed of this vessel? The boat had been stored in a garage for years. I drained the tank and cleaned the fuel lines. Put fresh non-ethanol gas in her and got it running. I took her out on the water on a calm day but could only reach a top speed of 20kts. The engins is a 302V8 the valve cover shows 188 and I'm guessing that is the HP. I've owned wooden Chris Crafts in the past but looking forward time with the Sea Ray. Any help wuld be appreacited.
Diagnostic over the net is impossible. But a couple things stand out. A 302 is a Ford engine. The famous 5.0. Ive raced Mustangs a while back.
I dont think a Ford was standard in a SR but i could be wrong as usual. I have a couple ideas but wont speculate beyond that. Start with finding out if that original engine. 1975 with 532 hours?
 
There were actually a number of years where GM or Ford were available. It "could" be the original... maybe not ;) But at this point, it's pretty much a moot point. It's still a small block so it's good enough.

From my experience with these boats over the years, I would think you should be comfortably in the mid-30's MPH - maybe even into the 40's. So right now, you're obviously short.

BUT... there are many, many factors that come into play such as... engine health (compression/leak down), tune up items, proper prop (pitch and condition), to name a few.

Also, and don't take this the wrong way, but operator error is right up there with common culprits. What RPM where you getting at max throttle? Were you trimming up as far as you could go till ventilation?
 
Diagnostic over the net is impossible. But a couple things stand out. A 302 is a Ford engine. The famous 5.0. Ive raced Mustangs a while back.
I dont think a Ford was standard in a SR but i could be wrong as usual. I have a couple ideas but wont speculate beyond that. Start with finding out if that original engine. 1975 with 532 hours?
I bought from the son of the original owner. The 302 is OEM. I've considered swapping GT40p heads from a 351W but
Diagnostic over the net is impossible. But a couple things stand out. A 302 is a Ford engine. The famous 5.0. Ive raced Mustangs a while back.
I dont think a Ford was standard in a SR but i could be wrong as usual. I have a couple ideas but wont speculate beyond that. Start with finding out if that original engine. 1975 with 532 hours?
I bought it from the original owner so it's a stock 302 w/2bb6 I should also mention that they just installed a new SEI outdrive in order to make it sailable. I put the recommended 10 hours breaking in the new drive. Still a little tight and need to replace the lubricant in the outdrive. The boat weights 3900 lbs dry according to the original literater.
 
There were actually a number of years where GM or Ford were available. It "could" be the original... maybe not ;) But at this point, it's pretty much a moot point. It's still a small block so it's good enough.

From my experience with these boats over the years, I would think you should be comfortably in the mid-30's MPH - maybe even into the 40's. So right now, you're obviously short.

BUT... there are many, many factors that come into play such as... engine health (compression/leak down), tune up items, proper prop (pitch and condition), to name a few.

Also, and don't take this the wrong way, but operator error is right up there with common culprits. What RPM where you getting at max throttle? Were you trimming up as far as you could go till ventilation?
Thanks. Compression is good. New SEI outdrive just broke in @10hrs and changed the fluids in the O/D.
I asked about the speed as I had the engine turning about 3000 RPM. i according to some forums (if you can believe the internet) hould rev out to about 4200?

I played with both the O/D trim and the trim tabs till the boat was level and getting the most speed.

I've heard a set of heads from a 351W 9GT40P) heads will bolt ruight up and because the angle of the block stay the same, I can reuse the 302 intake manifold. Before I go that route, I wanted to confirm that is currently under pefomring.and then go through the ignition system and maybe a SS prop? It appears to have a black aluminum orignal prop. The gentleman who sold me the boat said I would only get about 20kts but that just didn't seem correct.
 
What was the gear ratio of the new outdrive vs the old? Are you using the original propeller from the other drive? 4200 RPMs sounds like where you should max out.
 
Same O/D gear ratio and stock prop. I put the boat in a slip for a month in salt water and noticed it had a little growth on the bottom. I srubbed most of it off in the slip. Don't think there was enough to slow her down I will put a coat antifoulding on her before relaunching.

I'm going to start with new plugs and ignition. Probably rebuild the carb and see if I have any gains.
 
3000 RPM's was the MAX you could get? That's no good. 23MPH at about 3K RPM's is about right, though. Hard to say with some of the older boats, but newer boats would be a bit higher - maybe yours, as well. But you should definitely be getting into the low 4K range.

BUT... it sounds like, from what you wrote, that you didn't fully trim up as high as you could reasonably go. Take it for another ride... forget about the tabs for now... go WOT and keep trimming up till speed no longer increases or the prop ventilates. What speed do you get doing that?

Forget about the SS prop for now, as well.

Go to Sea Rays website and navigate to the prop matrix in the owner's section. Find your engine/drive ratio and compare the prop listed to what you have.

It only takes a TINY bit of growth to drastically slow a boat down. Get it ALL spic-n-span or any other tests are useless.

From what you've been saying... better trimming and a clean bottom could very well be all you need. Start there.
 
"23MPH at about 3K RPM's is about right" Agreed. S.E.I. break in routine is to keep it below 2k for 5hrs then push to w throttle, then back off, then wot for another 5hrs. Change the oil in the outdruve and supposedly I'm good to go.

I've have to investigate Sea Ray's site to confirm the correct prop size and gear ratios. I'll take your suggestion and take her out and trim her up and see if I can get some higher revs from her.

Thanks
 
MerCruiser used Ford V8's from 1971 through 1976, they stopped purchasing Fords after mid-late '76 and went to GM Marine. You noted an SEI drive (Sierra Marine's replacement of the MR drive), but your member notes identifiy it as an OMC /FORD 302. OMC stuck with Fords for some time after that with their stringer drives, and later to the Cobras. Yours is in the Stringer Drive years, and it shares many of the same foibles as what MerCruiser experienced. Here's the MCM circumstance as I am most familiar.. the exact same situations show up with OMCs both Stringer vintage, and COBRA.

I'm about 1200mi from my books, but IIRC, the Ford 302 appeared in 188 and mebbie 215hp ratings, the former being in I/O, and the latter as an inboard. Most that I've worked on were either identifed as the "188" or as the "888". Seems to me the 888 flavor had a 4bbl, but there wasn't a significant performance advantage.

The Ford V8's two biggest issues with these installations were weight, RPM, and fuel consumption. In marininzed trim, the Ford 302 and 351's were something like 180lbs heavier than the GM assembly, and FORD would NOT rate them past 4200rpm, whereas the GM systems were rated to 4800. The R/MR drive system was good for 4900 (don't go to 5k) and that extra 600rpm DID make a difference... particularly in fuel consumption, as to get up on plane and maintain, the Ford couldn't do it with gearing, it had to do it with fuel.

The Ford 351 version with 4bbl was identified as 233hp

The open-cockpit cuddy cabin brother to your hardtop is the 220CC, of which I own one 1977 fitted with a MCM 260R drive system (GM 350, log exhaust, 1.5:1 gears, 19" stainless prop, 46mph). It was originally fitted with a GM 305 identified as 228, and while I never tested mine with that engine (it was literally frozen, and in pieces when I got it), I have seen others, and they ran around 38mph at 4800rpm swinging a 17.

My Dad had a '76 220CC with the 351. It managed 40mph with a 19p at 4400rpm with an almost-empty fuel tank.

First thing is to empty EVERYTHING out of the boat that doesn't have to be there, then get the hull clean, and get yourself a three more propellers of different pitch. Clearly if you're only making 3000rpm, there's lots of horsepower left sitting on the table. You've either got some impressive drag somewhere, or the timing is way off, or you have way too much prop pitch. When you're at WOT, trimmed out, it should be at 4200. Once you're there, take a GPS reading.

Next thing to keep in mind, is that the hardtop and double-level windshield is somewhat of a sail, so the 220CC speed numbers I showed above, will NOT be within reach in your circumstance.

In the context of marine, I would NOT invest cubic money into the 302 to try and get more speed. Putting on different heads to get more power is NOT going to give any significant return... there's too many other puzzle pieces in the way. The best improvement you can get right now, is to determine why it's not getting to 4200, and it is probably a combination of prop diameter, pitch, and probably other adjustments.

One thing that I would certainly look out for, is ignition timing. On these engines, at this age, it is common for the exhaust manifolds, block, intake and head passages to be well-infiltrated with corrosion and crud. The castings will exhibit thinned-out areas, and hairline cracks will start to appear, but oftentimes won't leak, as rust/corrosion will nicely keep them sealed. The engine will run a bit warm from this, and the mechanic's reaction is to back off the timing, and try to swap in a lower-temp thermostat. Typically, the marine thermostat will be around 143F, I wouldn't be surprised if someone took the thermostat out (which is the wrong thing to do)... but the OTHER thing to really look out for, is the hose going from the forward side of the gimbal housing, into the transom plate. This is a 5/8" rubber hose that, under heavy engine load, can collapse internally and restrict cooling water flow from the drive into the engine. The next thing to look out for, is the power steering cooler located beneath exhaust manifold on starboard side. If you have crud on the outside of the boat, then there'll be crud built up on the heat exchanger's inlet side in this cooler... Crud, along with old fragments of aforementioned hose and any drive water pump impellers of the past WILL accumulate there, and restrict flow.

So look into those things FIRST. Don't dump money on cylinder heads, and the biggest reason, is that cylinder head flow is NOT a problem- the engine isn't turning fast enough to ever get there.
 
An esoteric note about break-in on MCM drives-

If one looks at the OLDEST service manuals, the break-in process was somewhat different, as was the tooth clearance and preload setup.

A few things changed over time.... and with the change from the R/MR to the Alpha, some design changes... two things that I've come across that sometimes catch us by surprise... is gear break-in, and preload of the upper drive bearing set.

The upper drive bearing set ORIGINALLY included a center spacer, shims, and some straightforward preloading... press the bearings in, then install the yoke and nut, tighten to x ft-lbs, and done. They eventually changed the design to omit many of those, and we simply press the bearing assembly together, then check the ROLLING TORQUE (which is usually much lower than what a 'torque wrench' can measure, so instead, a tensiometer instrument is used... but most pros I know just do it by 'feel', after having a few go's at it with the instrument. IIRC it was something like minimum of 5, maximum of 7 inch pounds... IMO Wayyy too sensitive a measuring scale for a practical field service action, and the proper instrument is certainly too expensive, and of too little use for an 'average guy'... but if you use a clamp-on winding drum, a string, and a pair of weights (no go, and go), it can be done...

The other is gears. Originally, gears were cut, polished, then lapped, then case hardened... and shipped as a matched set. For all the drives EXCEPT the 165, gearsets were an odd number of teeth, so that after a certain number of revolutions, one tooth will have been through EVERY OTHER, with the hopes that no 'timed wear' would occur between any two teeth. On the 165hp inline six, MCM had to utilize a 1:1 upper ratio (because the lower is already 1.65:1), and as a result, they could not avoid having repeating tooth pattern. Again, they originally did the cut/polish/lapping of the matched pair, but they added a timing mark to each, so that once assembled, the gears would run proper with respect to how they were lapped.

Move forward two decades, and the concept of gearmaking (and metallurgy) had changed, and they took advantage of some very interesting technology that had been developed mostly in the railroad and helicopter gearbox industry...

They cut the gears, gave them a cursory lapping, and then sent them out the door... with instructions to assemble them to a new gear lash setting... and if you had a 1:1 set (for a 165), they instructed you to punch timing marks into the gears once installed. THEN they included the new break-in procedure.

What happened, was that they utilized new alloys in the gearset that would, under proper loading, buff themselves into proper fitment AND work-harden their own surfaces. This eliminated many manufacturing steps AND provided a really good gear result.

And that's why there's such a rigorous break-in process involved.

What's the WORST thing a person could do? Start it up, and let it idle through the break in period. The gears don't get load, they don't wear into fitment, but they start to surface harden at the WRONG CLEARANCE... and then you wind up with noisy, short life, and all the baddish stuff that comes with it.

Now, one of the things that gearbox manufactures (especially the railway boxes I worked on, and some of the helo boxes that a buddy designed...) did... was to put the gearbox on a static load (basically, a jackshaft between input and output that 'wound up' torque against the running faces), and then they put a 2hp electric motor to spin the loaded gears, and brought it up to the appropriate break-in speed. I don't know if MCM or SIE ever did this, but if I was on the production engineering's reliability team, I would have made a preloading stand for fitting up drives in a temperature controlled water bath, and performed the breakin on the production line...

But they're not me, so who knows...
 
Looks like spam to me, and that's irrelevant to this circumstance, the boat was built almost 40 years ago, and had an advertised prop hp of 188... empirical data on these puts it around 29mph.
 
An esoteric note about break-in on MCM drives-

If one looks at the OLDEST service manuals, the break-in process was somewhat different, as was the tooth clearance and preload setup.

A few things changed over time.... and with the change from the R/MR to the Alpha, some design changes... two things that I've come across that sometimes catch us by surprise... is gear break-in, and preload of the upper drive bearing set.

The upper drive bearing set ORIGINALLY included a center spacer, shims, and some straightforward preloading... press the bearings in, then install the yoke and nut, tighten to x ft-lbs, and done. They eventually changed the design to omit many of those, and we simply press the bearing assembly together, then check the ROLLING TORQUE (which is usually much lower than what a 'torque wrench' can measure, so instead, a tensiometer instrument is used... but most pros I know just do it by 'feel', after having a few go's at it with the instrument. IIRC it was something like minimum of 5, maximum of 7 inch pounds... IMO Wayyy too sensitive a measuring scale for a practical field service action, and the proper instrument is certainly too expensive, and of too little use for an 'average guy'... but if you use a clamp-on winding drum, a string, and a pair of weights (no go, and go), it can be done...

The other is gears. Originally, gears were cut, polished, then lapped, then case hardened... and shipped as a matched set. For all the drives EXCEPT the 165, gearsets were an odd number of teeth, so that after a certain number of revolutions, one tooth will have been through EVERY OTHER, with the hopes that no 'timed wear' would occur between any two teeth. On the 165hp inline six, MCM had to utilize a 1:1 upper ratio (because the lower is already 1.65:1), and as a result, they could not avoid having repeating tooth pattern. Again, they originally did the cut/polish/lapping of the matched pair, but they added a timing mark to each, so that once assembled, the gears would run proper with respect to how they were lapped.

Move forward two decades, and the concept of gearmaking (and metallurgy) had changed, and they took advantage of some very interesting technology that had been developed mostly in the railroad and helicopter gearbox industry...

They cut the gears, gave them a cursory lapping, and then sent them out the door... with instructions to assemble them to a new gear lash setting... and if you had a 1:1 set (for a 165), they instructed you to punch timing marks into the gears once installed. THEN they included the new break-in procedure.

What happened, was that they utilized new alloys in the gearset that would, under proper loading, buff themselves into proper fitment AND work-harden their own surfaces. This eliminated many manufacturing steps AND provided a really good gear result.

And that's why there's such a rigorous break-in process involved.

What's the WORST thing a person could do? Start it up, and let it idle through the break in period. The gears don't get load, they don't wear into fitment, but they start to surface harden at the WRONG CLEARANCE... and then you wind up with noisy, short life, and all the baddish stuff that comes with it.

Now, one of the things that gearbox manufactures (especially the railway boxes I worked on, and some of the helo boxes that a buddy designed...) did... was to put the gearbox on a static load (basically, a jackshaft between input and output that 'wound up' torque against the running faces), and then they put a 2hp electric motor to spin the loaded gears, and brought it up to the appropriate break-in speed. I don't know if MCM or SIE ever did this, but if I was on the production engineering's reliability team, I would have made a preloading stand for fitting up drives in a temperature controlled water bath, and performed the breakin on the production line...

But they're not me, so who knows...
This is my first outdrive, I previously owned a 1962 Chris Craft Cavalier Express cruiser, and had to keep it in a covered slip on Lake Union, in Seattle. Lovely boat but higher maintenance and monthly slip fees. Prior to that I was in SoCal and had Santana 525 then an Olson 30. The appeal of this SR is I can park it in the off season and launch in the spring. Keep it in a slip till late fall. Plus it was built prior to Sea Ray's being acquired and merged.

Having no experience with I/O drives I followed the breaking in instructions from SEI, first 5 hours under 2k rpms, periodically throttling up for bit then down cycles repeatedly. Next 5 hours WOT then back down and repeat. After a total of 10 combined hours haul out the boat and drain O/D fluid and replace.

Couldn't get above 22 to 23 k rpms. It could have been a tight o/d and other factors. Since putting her in the carport for winter I ve replaced plugs and planning on going to electronic ignition, new plug wires, setting the timing and rebuilding the carb. As soon as winter thaws, I'm planning on painting antifoul on the bottom. Still need to check all electronics and upgrade the UHF radio, then install a Lowrance HDS live and am replacing all incandescent bulbs with LEDs, new zincs for the i/o, new batteries, change the oil, and flush the hydraulic fluid. Clean up the teak trim and relaunch in the spring.

The top speed I experienced seemed a bit slow to me but hey, this is my first SR, so what do I know? I really appreciate all to good support, information tips and suggestions from every post in answer to my initial question. The feedback gives me a target. I'll post the results when the weather thaws. In the interim I'm dealing with a frozen waterline in mv rental unit so back taking care of my tenant's needs took priority.

Thanks to all who replied for the good support and information. It has confirmed that I made the right choice in investing in a Sea Ray.
 
My Apologies, Columbia River- it's seemingly a common thing now for bots to create accounts and start posting links... but you're either not, or certainly a creative bot... ;) so HAM ON!

Okay, Mitch, so that helps a bit. Your 22 won't be a speed demon with the 188, but the fact that you're stonewalled at 3000rpm is certainly not right, and a thought occurred to me...

In MOST MCM V8's and V6's, the factory gear ratio (determined by that upper gearset) is 1.5:1. In the inline six, it was 1.65:1, and in the 4cyls it was usually around 1.98:1. There was a RARE variant of the Alpha One SS that came with a 1.34:1 (and they'll fit in an R, and that's what's in my avatar runabout).

What if... What if SEI fitted the wrong ratio to your 188?

It seems to me (and I'm 1300 miles from my books today, but I'm starting my drive home this afternoon)... that the 188 would've had the 1.5:1 gear ratio, but at that time, using one of the OTHER ratios was optional.

Typically, the standard ratio would always go out on a single-engine application, but where TWIN engines were used, it was not unusual to see one of the OTHER ratios used as an option. My '76 SRV-240 FB has a MCM-233... single R-drive behind a 351W... and the prop is a 15 pitch. There's another SRV-240FB that used to be around that had a PAIR of 165hp sixes... it was owned by the commodore of the other (not my) USCGA flotilla. HIS had, instead of 1.65:1 common to most, the 1.98:1 ratio. He swung a little more pitch AND more diameter than what my 24 would, and as a result, went faster, and got better fuel economy.

If your drive somehow (accidentally) wound up with a different ratio than what was original... that might explain why it's not breaking out of the 3's and into the 4k range. Unfortunately, if it WAS an accident, SEI probably stamped the wrong ratio on the side of the housing (it's on the tag, or in the aluminum on the upper housing in the tag area).

If you can't get any change by working the trim (as others noted, raise the drive until you get a little ventilation, then drop it back down a smidge), then haul it out, swap to a prop down 2" in pitch, and try it again, but keep the tach under 4500, and watch the engine temp gauge. Take GPS shots of your speed in each case so you have good data to compare.
 
My Apologies, Columbia River- it's seemingly a common thing now for bots to create accounts and start posting links... but you're either not, or certainly a creative bot... ;) so HAM ON!

Okay, Mitch, so that helps a bit. Your 22 won't be a speed demon with the 188, but the fact that you're stonewalled at 3000rpm is certainly not right, and a thought occurred to me...

In MOST MCM V8's and V6's, the factory gear ratio (determined by that upper gearset) is 1.5:1. In the inline six, it was 1.65:1, and in the 4cyls it was usually around 1.98:1. There was a RARE variant of the Alpha One SS that came with a 1.34:1 (and they'll fit in an R, and that's what's in my avatar runabout).

What if... What if SEI fitted the wrong ratio to your 188?

It seems to me (and I'm 1300 miles from my books today, but I'm starting my drive home this afternoon)... that the 188 would've had the 1.5:1 gear ratio, but at that time, using one of the OTHER ratios was optional.

Typically, the standard ratio would always go out on a single-engine application, but where TWIN engines were used, it was not unusual to see one of the OTHER ratios used as an option. My '76 SRV-240 FB has a MCM-233... single R-drive behind a 351W... and the prop is a 15 pitch. There's another SRV-240FB that used to be around that had a PAIR of 165hp sixes... it was owned by the commodore of the other (not my) USCGA flotilla. HIS had, instead of 1.65:1 common to most, the 1.98:1 ratio. He swung a little more pitch AND more diameter than what my 24 would, and as a result, went faster, and got better fuel economy.

If your drive somehow (accidentally) wound up with a different ratio than what was original... that might explain why it's not breaking out of the 3's and into the 4k range. Unfortunately, if it WAS an accident, SEI probably stamped the wrong ratio on the side of the housing (it's on the tag, or in the aluminum on the upper housing in the tag area).

If you can't get any change by working the trim (as others noted, raise the drive until you get a little ventilation, then drop it back down a smidge), then haul it out, swap to a prop down 2" in pitch, and try it again, but keep the tach under 4500, and watch the engine temp gauge. Take GPS shots of your speed in each case so you have good data to compare.
Good food for thought. When I have a moment I'll reach out to SEI with to determine what the ration. previous owner purchased last year to confirm.
So many things to tweak before I can do a fair evaluation of it's present state. The plugs looked like the originals when I replaced them as were their wires. I'm anxious to see how she behaves after a proper tune, carb rebuilt and gas tank/ fuel line flushing. I considered replacing both the engine and drive but as I have learned the hard way, it's always easy to waste cash attempting to correctg a situation before making a full and complete evaluation. I'd kinda like to keep the boat as a frugal investment. Tere is always plenty of time to burn cash. Time will tell. I'm trying to avoid making B.O.A.T= bring on another thousand my reality. :)
 
Once it's in a good state-of-tune and running to full RPM, you might find desire for more power, if not for the ability to cover more distance in shorter time, the ability to get to a higher state of plane, lose some drag, and gain some fuel efficiency.

IF you have a MerCruiser drive, changing your 302 for a GM Marine 350 is fairly straightforward. If yours is an OMC 'stringer drive', then you're in for a significant rework which isn't impossible, but it'll be involved. A MerCruiser 5.7 with either an R/Alpha or Bravo from a donor boat would be my recommendation. Replaces cubic money investment with a few gallons of sweat and busted knuckles.
 

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