1998 230 Overnighter - Loss of thrust

[TippyCanoe]

I just purchased a new to me 1998 230 Overnighter with a 5.7 L 250 HP and Alpha One drive. The boat only has 250 hours on it and runs great. I had it checked out by a repuatable marine mechanic before I purchased it and had him install a new 3 blade aluminum prop 15x17 i think. I took the boat on a vacation to a lake and it ran great until the last day. While running around it seemed the I lost some power or speed. I thought I hit a stick or something so I immediately checked and nothing. The boat runs normal up to 3000 rpms but then seems to not have anymore thrust. The RPM's go up but the speed stays the same. Any ideas? Could this be a spun prop? It seems I was running about 30 MPH at 3200-3400 RPM's before but now only in the low 20's at the same RPM's. What should I epxpect from WOT for this boat? Any prop suggestions?

 

[TippyCanoe]

I hope it's not the coupler! The engine and drive only have 250 hours so I would think that the coupler would be good still. What causes a coupler to go bad? Is that something a mechanic would see during an outdrive service. It recently had one. Also, the pro and hub are new, how likely is it for the hub to spin when new?

 

[Gary Hill]

Typically, the coupler wears when the engine and outdrive are out of alignment. Can the coupler wear out in 250 hours. Yes. The spline of the outdrive is harder that the female spline of the coupler and will wear on the coupler spline if out of alignment and / or not greased properly. Can the mechanic see a worn outdrive spline, yes if, the drive was removed. Can the coupler spline be seen when the drive is off, yes. However, harder to see wear in there. Should the alignment be checked with outdrive service, depends on what you paid for (but it should be checked regardless, IMHO).

If your boat is on a trailer, put the shifter in gear (battery off, keys off and out for safety!!!!!!!!!!!) and then try to spin the prop. you should hear and feel clicking in one direction and resistance in the other. In the direction of the resistance, try pushing harder, like with your foot. If your coupler is bad you will be able to spin the prop albeit slowly. Otherwise you would be spinning the engine which would be very difficult to do at the prop. If the prop turns and not the shaft it would be the hub. If the prop and shaft turn together it is most likely the coupler.

 

[SeaRide]

Tippy,

I would be surprised if the problem is the coupler. Typically speaking, the coupler is either spun or it isn't and is accompanied with the smell of burnt rubber. I partially spun a prop. hub in the '80s and it exhibited similar issues as you have described. As I recall, the hub would start slipping around 3000 rpm and continue to do so even if you backed off to 3000 rpm. So, I would come off plane and nurse it back to 3000 rpm and off we went. This boat was powered by a MerCruiser 260 (350 w/a 4V). However, years ago, Merc. used a rubber bushing style hub rather than the current "plastic" Flo Thru Torq Hub. The prop. shop overhauled the propeller and inserted a new hub. That resolved the problem. Who knows though the same principal could apply to the coupler. I have yet to hear of it, though.

Good luck and let us know what the problem is.

 

[TippyCanoe]

I tried spinning the pro with the boat in gear and in the direction of resistance I was able to sping the prop slowly. Now I'm a pretty large guy and did put some muscle into it. The shaft did spin with the prop as well. I guess it sounds like it could be the coupler? Is there anything else it could be? I haven't had a chance to take it back out on the water to test it. My mechanic said when a coupler is spun that you are generally getting a tow back in. That leads me to believe it might be ok.

Tippy

 

[TippyCanoe]

I took the boat out a few times last week and did not notice the problem again. I was able to reach 41 MPH @ 4600rpm on the GPS. I haven't had the boat long enough to find my true WOT. The issue I noticed this week is it doesn't clunk into and out of gear and sometimes seems to stick in gear when I try to take it out. Is this a shift cable adjustment issue?

 

[SeaRide]

Tippy,

I have never had any shifting issues over the last 14 years. However, I can also tell you that I have also had my shift cable replaced at the last bellows change, which was just over five years ago. This may or may not be your probem.

As far as speed is concerned, you are probably pretty close to book speed. Max. speed for my 230 Bowrider per the Sea Ray specs. is 43 - 47 mph (trimmed up) with a 5.7 EFI and a 17" pitch Vengeance (stainless) propeller. WOT spec. range for my 5.7 EFI is 4400 - 4800 RPM. I am sure SR runs their numbers under very light loads. My boat tends to run on the upper end of the scale. The best top speed I every witnessed was about 50 MPH on a cool Feb. boat without the bimini top and just me on board. During the summer I still see about 47 mph with the bimini.

 

[TippyCanoe]

Thanks SeaRide...What prop are you running? The 17" pitch Vengeance? I would like to see my speed closer to 45. What speed are you cruising at in the 3200-3400 rpm range. I see you have an EFI which gives you a little edge over my no FI engine.

 

[SeaRide]

Yes Tippy. The speeds I quoted were with the 17" Vengeance. However, for the past several years I have been running a 19" High Five Stainless. Top end and overall performance is nearly identical to the Vengeance. Depending upon loads, 3,200 rpm will equal about 31 mph (gps) with my High Five. I can check this weekend if you would like and exact figure. My EFI is rated at 260 HP. Who knows, the extra 10 HP may have been found by the marketing department. I suspect our engines put out the same amount of power. The 50 MPH speed I quoted was also back in the 2002 - 2004 time frame. The 47 MPH summer top speed is still valid when lightly loaded with the High Five.

All the reports I have read indicate the Mercury's new Enertia series offer the best acceleration, top speed and etc. I do not know of anyone on the board who runs one.

 

[Gary Hill]

I took the boat out a few times last week and did not notice the problem again. I was able to reach 41 MPH @ 4600rpm on the GPS. I haven't had the boat long enough to find my true WOT. The issue I noticed this week is it doesn't clunk into and out of gear and sometimes seems to stick in gear when I try to take it out. Is this a shift cable adjustment issue?

Tippy, this is good. At least in regard to the coupler. The odds of it being the coupler are pretty much zero. I have seen one case where a guy never greased his spline/coupler assembly and when the spline shaft spun it created enough friction that the two friction welded together for a short period. Very, very rare. Yes, you need to look at your cables. Also there should be a switch that kills the engine for a split second when shifting that may need adjusting. One of the boats here in the marina had a problem with the switch and it dorve him and the mechanic crazy as it was an intermittent problem.

Regards,

Gary

 

[CliffA]

My EFI is rated at 260 HP. Who knows, the extra 10 HP may have been found by the marketing department. I suspect our engines put out the same amount of power.

it is not unusual for a fuel injected engine to put out higher hp than the same size carb'd engine....the FI engine utilizes the fuel more efficently than a carb'd engine.....i have the same carb'd 5.7 rated at 250 hp......

cliff

 

[SeaRide]

it is not unusual for a fuel injected engine to put out higher hp than the same size carb'd engine....the FI engine utilizes the fuel more efficently than a carb'd engine.....i have the same carb'd 5.7 rated at 250 hp......

cliff

I, agree Cliff, but I have the TBI system which has two injectors sitting atop of the intake manifold. So, essentially, I have an "electronic 2V carb." So, you are right it may really put out more than the carbed version. Engine manufacturers have can fudge the numbers for marketing reasons. It's also possible that Merc. did not want to rate my 350 at 270 HP as that would put it too close to the 350 Mag's 300 HP rating. So, if there is really only 10 HP difference between the two engines, I would be really surprised if the difference showed up on the speedometer.

 

[CliffA]

So, if there is really only 10 HP difference between the two engines, I would be really surprised if the difference showed up on the speedometer.

agree....10 hp is not that big of a deal relating to performance but it can be a good marketing tool.....

cliff