2000 Sea Ray Sundeck 210 HELP!

boater2018

Member
Feb 26, 2018
146
Boat Info
2000 Sea Ray 210 Sundeck
Engines
Mercruiser 5.0 EFI
I purchased a used 2000 Sundeck 210 that needed a lot of work. The previous owner purchased it from the original owner, who seemed to neglect the boat. Originally, the boat came from Savannah, GA and had 220 hours on it. The previous owner told me that when he purchased it, the engine block was cracked so he replaced it with a "Vortec 5.7 from a truck". To cut some of the story out, I purchased the boat, as it did run and crank, but idled rough and had timing issues. Upon farther investigation and many hours of work, I discovered the engine serial number plate on the block and it was a mercruiser marine plate and the serial number traced back to be a 1994 5.0 litre (original motor was a 5.0, EFI). 2 different marine mechanics "looked" at it, the first one adjusted the timing, did a few maintenance items, said they water tested it and I should be in good shape. When we took it to the water, we found that it wouldn't go in reverse without going dead. A new shifting cable later, took it back to the water and it wouldn't plane out. The 2nd mechanic, after 3 weeks, adjusted the timing in the water (don't know if they finished) got the boat to plane out, ran it up to 42-4300 rpm, said it lost oil pressure, said I needed to replace the motor. Being that the boat cranks smoothly, runs smoothly and planes out, has no knocks, makes no noises of any kind, I thought they didn't investigate very much and couldn't rely on their suggestion. They told me it acted like an auto engine, because the oil pressure dropped, however, it has a mercruiser badge on it that looks original, so it's hard to believe. I checked pressure with a mechanical guage myself and the engine held 50 lbs of pressure, no problems, so I replaced the sender unit, seems to be good now. We used the boat several times last summer and never had any problems cranking, running and seems to run smooth. The only issue is it seems to be VERY slow planing with only 2-3 people on board, including myself and not much gear at all. I didn't clock it, but it the acceleration had much to be desired and seemed like it was lacking greatly. Also, I ran it up to around 4,200 RPM (if memory serves me correctly) and clocked it at 33-34 mph on a gps with the trim all the way down. The speed doesn't match the rpm at all at any point of acceleration. It has a knock sensor that was very rusty and looked like it was in bad shape, so I replaced it just now. I also plan to replace the plugs and wires as I'm sure they are past due. Any other ideas of what could cause this? Could it need more timing adjustment? or the knock sensor (Sierra replacement) be the problem? It has the factory SS 14x19 prop, looks to be a decent condition, one edge slightly rough, but doesn't seem to be enough to affect it.
 
Boy, seems like you were really getting the run around there... ALL around! But the things you have done are in the right direction. Add cap/rotor to your "to do list". Timing could certainly be out.

Because of the design on the boat (seat way in the back), it was never a super-fast-to-plane boat. Especially if people were sitting on that aft seat (and, of course, their actual weight). But I wouldn't say that it "plows" forever and ever, either. You could add some dead weight in the anchor locker or bow seats to help with planing.

Be sure you have it trimmed all the way down on take-off (physically verify that it is indeed going all the way down), then trim up once you're on plane. You want to trim up to get your best top speed and efficiency. You should be able to get around 4,800RPMs with just you in the boat and be doing low to mid 40's for speed. BUT, you have to trim up to get that.

Adding trim tabs (something inexpensive like Smart Tabs) is an option to greatly help hole shot - but ONLY after you are positive it is running well.

If there is ANY growth on the hull bottom, that has a big impact on performance.
 
I 2nd Lazy Daze. Once up on plane I trimmed out and was able to get to 45-48 mpg @ around 4800 rpm.
 
Thank you for your response. My brother has a 2001 210 bowrider that my dad bought new and it planes really good and it planes very quickly. I'm just used to the way it runs and have never ridden in a Sundeck. The trim does go all the way down and that is how I have it trimmed to start. A local marine mechanic (Not either of the ones that has looked at it) suggested I might change to a 17 pitch prop.....he talked like he's seen a lot of guys doing that to help hole shot on boats similar in size to mine. This is probably an obvious observation, but when I slow down from being on plane, it is very slow trying to re-accelerate. It is definitely lacking acceleration though.

It is digital timing with an ECM
 
I'll guess what happened with your engine. PO replaced the block with an old 94 5.0 and bolted on a set of Vortec 5.7 heads and used the induction and ignition system off the original 2000 5.0. If this is the case your compression ratio is way down.

Check compression , see if you can get a casting number off the heads.
 
Pulled 1 of the valve covers tonight...97 305 matched the casting number, so I figure that’s the original heads. Should be 305 block & heads...i’m thinking I need to proceed with plugs and wires, and get the timing checked under load
 
Changing the plugs? Take the extra time and do a compression test (As previously recommended)


Remove all plugs
Hold throttle wide open
Disable fuel pump
Keep the battery on a charger
Don't forget a water supply to the pump.
Do a "dry" test first, then a few squirts of oil into the cylinder for a "wet" test.

Post the results here
 
I'm not a mechanic, so I've been researching how to do a compression test. I found a Mercruiser service bulletin and this is my understanding:
1) Remove all spark plugs
2) Remove wire from center of the distributor cap and ground it to the main engine ground
3) Use a fully charged battery
4) Open throttle completely
5) Start with the compression gauge at "0", crank the engine through 4 compression strokes
6) Record compression for each cylinder

It doesn't mention cutting of the Lanyard Stop Switch or using a Remote Starter as a requirement.....
Is anything farther required? Fuel pump or water supply related?
 
Still not following along with your combination of parts.
94 block and 97 heads ? Around 96 or so GM changed the heads to Vortec style. With that style head your compression readings should be in the 175/180 range. Pre vortec 150 would be a good number.

Just unplug your fuel pump, lower port side. I personally don't sweat the water part. Warm up the engine a bit . If you have a lanyard you could disconnect that instead of the distributor wire.
 
The original motor serial number traces as a '98 and newer Mercruiser 5.0L Alpha/Bravo EFI. The previous owner informed me the block was cracked due to freezing so he replaced it with what he said was a 350 Vortec (Auto engine). The block actually has a Mercury Marine badge on it and the serial number traces to be a 1994 5.0L block. So, it appears the block is a 1994, other components (heads, TBI, exhaust, etc) are the original parts. I am thinking even though the casting number on the heads (12558059) shows to be a 1997 when searching it, that they are the OEM heads. I think he thought is sounded better saying it was a 350 than a 305, so he lied....but I really don't know why he told me it was a 350 as a 305 would have meshed up better with the OEM parts anyway. Engine runs smooth, cranks good, just very slow hole shot with a small crew, but it does plane out and hit 33-34 mph trimmed all the way down. The timing was awful when I bought it, but it sounds smooth now, however, I don't know that either mechanic that looked at it completely finished adjusting it while under load as the 2nd mechanic that adjusted it and then it planed out, stopped because of "low oil pressure" which he only tested electronically and I verified good oil pressure with a mechanical gauge. The mechanics that I have used to date have been more trouble than help....

1st mechanic said it was good and water tested....then I figured out right quick that was a lie (not planning out & shifter cable wouldn't allow it to go into reverse & steering cable was bad)

2nd mechanic got it to plane and did some work on the timing.....water tested it....told me it wouldn't hold oil pressure and quoted a new engine for 6k. I took it home thinking it ran awfully smooth to not have oil pressure and it held 50 lbs verified by a mechanical gauge. I ran it all day on the lake with that gauge hooked up, held good pressure the whole time. I really think they just didn't want to mess with it because they're a dealer and were busy with other things, probably newer boats

And before all that, the guy that sold it to me said it had a 350 and it has a 305 block according to the badge that appears to be the original badge....

Run around is putting it very lightly
 
I really appreciate the valuable advice you guys have sent....I'll post progress as I am able to test farther. If any other ideas come to mind, feel free to post.

I also replaced the knock sensor, which looked awful and am told could have an effect on acceleration and timing (might be the only problem)
 
Still not following along with your combination of parts.
94 block and 97 heads ? Around 96 or so GM changed the heads to Vortec style. With that style head your compression readings should be in the 175/180 range. Pre vortec 150 would be a good number.

Just unplug your fuel pump, lower port side. I personally don't sweat the water part. Warm up the engine a bit . If you have a lanyard you could disconnect that instead of the distributor wire.
It is an EFI, I saw on another post where opening the throttle was all that is necessary...do I still need to unplug the fuel pump. Sorry for the questions, just somewhat dumb on this, but looks simple. Again, very much appreciated
 
You should be able to see the discharge nozzle on the throttle body. If gas isn't coming out when your cranking, your good.
 
You don't need to mess with the distributor wire (or the fuel pump for that matter... although there's nothing wrong with doing that). Just flick the kill switch to "off", open the throttle, crank. You should get final compression in 3 to 5 puffs. But keep cranking if the needle is still rising and note that. It's "best" to have water to the impeller, but not entirely necessary as you're not cranking that long and the engine is only turning cranking RPM's. Personally, I like the water still going - but if you just ran it, it's still kind of wet down there and good enough.

I'll mention this ahead of time, as I'm sure you're going to ask... The compression #'s from the 8 cylinders are most likely NOT going to be the same. That's normal. But I'd like to see them all within about 10% of each other. 15% isn't horrible, yet.
 
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I ran a dry compression test this weekend. The boat has been in storage for the winter, so I did not crank it and let it warm as I don't want to have to re-winterize it. These are the cold numbers:
1-142
2-150
3-143
4-142
5-149
6-142
7-150
8-150

I saw where another guy did the same test with a boat that had been sitting up for the off-season with similar results. For his curiosity, he did another test once he had the boat in the water and warmed up and his numbers increased 20 lbs. I feel we're in good shape on the engine's compression. I also pulled the distributor cap to inspect and attached files here. The plugs were definitely past due and fouled. The rotor looked clean, but I'm assuming the cap needs to be replaced by the look of the posts and I might as well change the rotor too. Also, have you guys ever cleaned the arrestor on top of the throttle body? The manual just says to use solvent, any preferences on what to use for soaking/clean that? Thanks again!
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Compression is fine. Cap is fine - that's the not the problem. If plugs were really bad, that "could" be it. May need to wait till you get this in the water and re-test. If everything that's been mentioned checks out, may need to do a leak down test.
 
Here's some of the plugs...they all were like these. It also appears to have the original plugs wires on it from 2000, which I am replacing. The routing may also be off some, if that matters. I plan to follow the diagram in the mercruiser manual when replacing. I put the new knock sensor on there. Right now, I am thinking finish replacing the plug wires, have someone check the timing and make sure it's good or fine tune, if needed as I'm not sure they ever "finished" adjusting it....put it in the water and see if it's better. Thanks again for your help on this. It's been a rollercoaster for a non-boat mechanic, but I have learned a lot through the process.
Plugs.JPG
 
It's hard to tell the plug condition from that picture, BUT.... "routing may be off"? Do you mean the plug wire routing - as in two plug wires are going to the wrong spark plugs? If that's what you mean.... BINGO! Probem solved. Although I'm surprised the engine ran as it good as it did.
 
It's hard to tell the plug condition from that picture, BUT.... "routing may be off"? Do you mean the plug wire routing - as in two plug wires are going to the wrong spark plugs? If that's what you mean.... BINGO! Probem solved. Although I'm surprised the engine ran as it good as it did.
When I say routing, I'm thinking about crossfire, one wire crossing another it's not supposed to....or not crossing another it is supposed to, but not necessarily going to the wrong plug. I hope the Mercruiser mechanic at least got that right, and surely he did considering it does run smoothly. Could the knock sensor cause the problem, if it was bad? I tried to test it, but I don't think I did it correctly, but I did put a new Sierra brand on anyway, so surely it works now, however, it was used with the "old" sensor and I have not had it in the water with the new one yet.
 

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