Boat doesnt want to start while in the water

[Pbdy Jr]

PLEASE HELP!! Boat starts and runs in driveway.In the water,does not want to start.

Okay, so this season my boat decided to give me a hard time... I was out on the lake as normal and when it was time to come in, i pulled up my anchor and went to start the motor.... It just kept turning over. Eventually it started, It ran fine, no sputtering, misfires etc... I got it on the trailer and took it home. Hooked up hose and it started right up. Changed plugs, wires, dropped the lower unit on the Alpha 1. Impeller is practically brand new. Still fires right uo in the driveway. Brought it to the water and same thing.
What is causing this to not run right in the water?? while it turned over i sprayed some engine start spray and that did nothing. carbs clean, fuel flows fine. no wiring issues can be found.. When the boat is in water, the only thing I can think of is the water creates pressure which is effecting something... but what??

Mercruiser 3.0 with Alpha 1

 

[Bondo]

Mercruiser 3.0 with Alpha 1

Ayuh,.... What Vintage,..??

Is there Power at the coil's (+) terminal, when it won't start,..??

 

[Pbdy Jr]

this is a 1997.
I have not checked the terminal while it is in the water,. In the driveway theres power to everything.
Is there any type of logical explanation that the coil wouldnt have power ONLY when the boat is in the water.

When the motor is turning over, it does not even sound as though it is trying to start. I guess my next step is to check for spark during this period. But again, what logical explanation would that be? fires right up out of water but not in. Eventually after a while it starts up. I thought maybe a timing issue, but what can cause the timing to be that far off? How do I test for timing without a tool?

Basically, what should my next step be

 

[Bayou Dave]

Is there an ignition control module on it? Some times those things work and some times they don't.

 

[Pbdy Jr]

Of course I can be wrong here... No i do not believe there is an ignition control module on it. There is a module on the distributor. Is this what you are referring to? But again works out of water but not in"?

 

[Bayou Dave]

Of course I can be wrong here... No i do not believe there is an ignition control module on it. There is a module on the distributor. Is this what you are referring to? But again works out of water but not in"?

The one on the distributor is the one I mentioned. I don't know how to test them, but sure someone else will come along with the method of checking or have some orther ideas about the problem.

 

[Pbdy Jr]

I have been thinking about this a lot. Must be something to do with the change in pressure/load. Or maybe an issue with the exhaust shutter.. Is that possible?
Before I start taking things off Im trying to find the right place to look.

I must stress this.... It starts immediately and runs great (in the driveway with the muffs on) but in the water.... doesnt seem to want to cooperate.

 

[Bt Doctur]

what dosent it do?

 

[Pbdy Jr]

turns over strong while in the water but takes a looonng time to decide to start. This is only a problem in the water. Was wondering if the exhaust shutter could be not letting air in or something.. Stopping it from firing up. Just a guess. New plugs, new wires. Full tank of gas. Runs great when its running. If i shut it off and anchor to fish/swim,etc... doesnt want to start up when its time to go again.
Not overheating Doesnt sputter at all when running.

The only other repair done to it this season is the alternator belt snapped and was replaced.

Lower unit dropped, impeller is in excellent condition.

 

[Bt Doctur]

Are you opening the throttle a bit? Is this a carb motor?

 

[Pbdy Jr]

it is a carb. Yes I open the throttle a little and then as i keep turning over and it not even coughing, i opened the throttle fully. Sprayed starting spray in there and it still no cough.
Eventually it decides to attempt to start and one pump more of the throttle and were on... Its very strange though that it only happens in water and up until it actually starts, it doesnt even sound like its trying, other than the cranking of the engine.

Carb is clean and once Im running in water, or in the driveway, it runs strong, no bogging, sputtering etc...

Any Ideas?

 

[Pbdy Jr]

Can the starter be weak? it sounds fine. Turns the engine no problem. Maybe the load of the water makes it harder?

 

[Bt Doctur]

I would say your not pumping the throttle a few times to start it.Some motors need a few shots of gas to get going hot or cold.

 

[figaro]

any chance its flooded or flooding on your trip over to the boat ramp and down the ramp into the water ?.. add the choke into the mix and it could create an extended crank .. hows it run when it does finally start ? rough , rich etc

 

[Pbdy Jr]

Yes, that is with pumping the throttle.. It runs beautifully. No stuttering no backfire no misfires. The plugs are brand new this season but I pulled them to check and they do have some carbon deposit on them

 

[Bondo]

Ayuh,..... It'd be nice to know What motor, What carb, 'n What vintage We're talkin' 'bout,....

 

[Pbdy Jr]

1997 mercruiser 3.0. I/O unsure carb model.

 

[flipbro]

Mabe its flooding. Next time try holding it wide open dont pump it see if it fires up. If it does its flooding. When it does start is there a bunch of carbon floating in the water behind the boat? Have you verified the choke works properly?

 

[Pbdy Jr]

So we can clear all those as the problem. In addition to all that I have brand new plugs and wires. A new starter solenoid. I'm desperate at this point. Terrified that I'll be stuck out there. What else could this be.

Jopes, have you checked the timing lately?

 

[jopes]

Yes, I just put in the new delco voyager ignition and distributor. New wires, new plugs, new tstat because mine was stuck open.

It is not over heating because it is the same on a cold or warm motor. Let it sit in the water a few minutes off and crank, crank, crank... Replaced battery cables with heavier gauge. Starter wheels the engine over very fast. Once it is running it stays running.