Wot?

[wallydc2]

I cannot seem to get WOT out of my 3.0L mercruiser. I installed new plugs and I have a stone and carburetor filter on order. I'm not sure if changing the filters will help but it can't hurt. Right now I am running a 19 pitch propeller and I am only getting 2800-3000. I tried my 17 pitch and of course I only get an extra 200rpm which may get me 3200 or 3300, I should be getting 4200-4600. Any of you guys experience a problem like this? The engine is in a 1991 17ft regal valanti so size isn't the issue. I have inspected the carb and cant find any leaking inside if that could be the problem. But I do notice a strong gas odor when I shut it down on the lake to let the kids swim so I run the blower before I start it up to avoid an early independence day. If anyone has any idea why I cannot reach WOT please let me know. By the way all 4 of us weigh less than 500lbs.

 

[Don S]

Re: Wot?

List of possible causes of low WOT.

Engine Won't Reach Operating RPM. Check

• Fuel condition. Type and Octane possibly old fuel
• Propeller pitch or diameter, damaged blades
• Restricted fuel pickup tube or anti siphon valve Fuel System Test
• Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
• Marine growth on hull and outdrive
• Wrong gear ratio in outdrive
• Restricted carburetor air intake (clogged flame arrestor)
• Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
• Poor cylinder compression Compression Test
• Carburetor defective, or wrong type.
• Fuel pump pressure and vacuum
• Boat overloaded, improperly loaded, or improperly trimmed.
• Engine Overheating
• Engine timing and ignition system operation
• Remote control cables and linkage for proper travel to open throttle plates fully.

 

[watermellonI]

Re: Wot?

I m no expert but it sounds, and smells, like you may not be gettin fire on all 4cyl, check your plug wires, distributer, if your not leakin fuel anywhere you can find then its probably not burning in the cyl thats why you smell fuel at shut down, make sure you didn t cross a plug wire, and the wires are all seated good n tight, that gives u a place to start, till the experts have get here

 

[wallydc2]

Re: Wot?

I hear you but would'nt the engine be running rough if it were only running on 3 cylinders? Actually it runs really good just cant get the proper WOT. I'm not doubting you, maybe I would'nt know if it was running on 3 cylinders

 

[ziggy]

Re: Wot?

go thru dons' list. you'll likely find that one of thems items is the culprit. ya may be able to shorten the list a bit. as the smell of fuel vapors is not normal. seems that'd lead ya in the direction of a fuel issue of some sorts.....there's 5 items on that list that are fuel related, read the fuel system test. theres more items that can be eliminated in that artical....eliminate them, one by one.....if that don't fix it. there's more items to be eliminated too......

 

[180shabah]

Re: Wot?

I hear you but would'nt the engine be running rough if it were only running on 3 cylinders? Actually it runs really good just cant get the proper WOT. I'm not doubting you, maybe I would'nt know if it was running on 3 cylinders

You would know if you had a completely dead cylinder.

 

[RatFish]

Re: Wot?

I had a spark plug wire fall off on 5.0L mercruiser. Only way I noticed was reduced RPM. Follow Don's list, he knows his stuff. Helped me many a time.

 

[wallydc2]

Re: Wot?

Thanks for all the advice, will follow don's list and let you guys know what I find out and hopefully help the next guy.

 

[180shabah]

Re: Wot?

RatFish, a 5.0L V8 is not a four cylinder. That slight vibration on your engine(one dead cylinder) is a pretty substantial shake on a 3.0, especially if there is any load applied to it.

 

[wallydc2]

Re: Wot?

Ok, I started with the carburetor filter. Once I finally got it off without tweaking that steel line which is easy to do if you are not careful I found a stone filter inside with a spring behind it. The Marine dealer sold me a screen type filter. Can I use the screen instead of the stone? Is the screen what needs to be in there?


P.S. I read were a guy broke his steel line earlier. I sprayed mine with lubricant and let it sit for about 10 minutes and it finally came off without having to be replaced.

 

[wallydc2]

Re: Wot?

Ok guys, performed all of the tests Don S. sent 120-122 on all cylinders, no fuel in sight tube disconnected fuel line to carb and ran it into a jug. Turned over engine apprx 8 times and it filled up a little over half way. No fuel leaks found on any hoses. Those little exhaust holes in the transom dont seem to be clogged although one releases air and mist and the other all water. Still smelling more fuel than I think I should. There is a hesitation when throttling up, I think someone said that sounds like the accelerator pump? The only thing left is the carb, any other ideas?

 

[antsmands]

Re: Wot?

Wallydc2;

It's your carb. Get a rebuild kit and rebuild the carb. Should take care of your problem.

antsmands

 

[wallydc2]

Re: Wot?

It's on the way, will let you know the outcome.

 

[Bondo]

Re: Wot?

Wally,........ What's the History on this craft,....... Have You ever seen the proper WOT,..??..??...

Or is this New to You,..??..??......

If it's New to You,.......... I'd bet the Wrong Outdrive has been Installed.......

#6, Wrong gear ratio in outdrive

You're right about where it otta be with a V8 outdrive..........