New engine problems!!!!!!!

[Karbo]

First off this is my first post ,so hello all. I'm having problems with my new motor I installed on my boat. <br /><br />First let me explain a few things. I have a 1989 Rinker Festiva 230 cuddy cabin I/O. The origanal motor was a mercruiser 305. But the boat sunk because of a crack in the molding that holds the top and bottom of the shell of the boat together. <br />I replaced the motor last year late in the season with a 350 merc (its actually a chevy 350) but I'm having problems. The boat starts and runs fine.....until it gets hot, then it cuts out and wants to stall! I can run it at idle speed with no problem but if i try to plane out it wants to stall. The guy who installed the motor (a friend not a dealer) said it might be the module inside of my distributor cap. I replaced that...$90.00!!!! No luck, still wants to stall. A friend of mine said it may be a sensor or something? Does anyone have any idea what could be causing this problem? Anyone ever have similar problems?Any help would be appreciated. <br /><br />Thanks <br />Joe

 

[snapperbait]

Re: New engine problems!!!!!!!

Hi Joe.. Does the engine have a Carb, or is it EFI (fuel injection)?.. <br /><br /> Does it want to pop or backfire before it stalls?<br /><br />If it has a carb, you can rule out sensors... It would'nt have any... <br /><br />I'd check to make sure the ignition timing is adjusted correctly at idle, with the engine warm... Carb rebuild, or some carb "tuneing" might be in order..

 

[Karbo]

Re: New engine problems!!!!!!!

yes it is a carb motor.the carb was rebuilt when i put the new motor in. the timing was set the last time i took it out. the cap, wires, and plugs are all new as is the fuel and oil filters.<br />No it doesnt backfire or anything like that...It runs fine till it gets hot...then it just cuts out, loses power and wants to stall.<br /><br />hmmmmm!

 

[Boomyal]

Re: New engine problems!!!!!!!

can you duplicate it on the muffs?

 

[Karbo]

Re: New engine problems!!!!!!!

haven't tried it in the muffs. I don't think it would be good to go full throttle with the muffs on, would it?

 

[Boomyal]

Re: New engine problems!!!!!!!

No it wouldn't Joe, but I'd be trying to determine if it is temp related, rpm related or load related. If, when warmed up, you can rev it in neutral but stall out when under way I would begin to suspect a failing fuel pump. They do not necessarily go out all at once.

 

[f_inscreenname]

Re: New engine problems!!!!!!!

Who rebuilt the carb? It is so easy to screw it up if not done right. Sounds like it happens when the bow is high and the carb is tilted back. If the floats are not set right you will starve the motor of fuel and it will die. Then there is the accelerator pump. If it is not right it will not pump enough gas into the carb on take off and the motor will bog out.

 

[rattana]

Re: New engine problems!!!!!!!

It sounds like it is running out of fuel. You may have to recheck the float settings and the fuel filter.

 

[snapperbait]

Re: New engine problems!!!!!!!

If it was running out of fuel, i'd think it'd backfire or pop a little when it leaned out.. <br /><br />Might check voltage too the coil... Might be a bad ballast resistor or resistor wire not letting enuff voltage to get to the coil.. Maybe a weak coil.. <br /><br />If you could, check the voltage at the + terminal on the coil while the engine is hot and wanting to stall.. Should be at least 10.5 volts at idle, and voltage should rise from there as the demand for voltage to the coil goes up...

 

[Rainmaker]

Re: New engine problems!!!!!!!

May want to check if the spark is advancing. (However, I don't know anything about Merc distributors. Is the spark advanced with weights and springs or does the module handle advance?)<br /><br />If advance isn't working it will rev up fine on the muffs, but not under load.

 

[Karbo]

Re: New engine problems!!!!!!!

Someone on another forum said it may be a vaporlock problem. It does sound like when my vent cap was plugged up, I replaced it and the boat ran fine....But that was before it took the plunge. Maybe the vent tube is plugged up with some river mud.That would explain why it runs normally after I let the engine cool down and the pressure in the fuel tank dissipates. What do you guys think?<br /><br />My boat is dry docked in storage and I wont be able to get to it till this weekend. So I'm trying to get as much advise as I can before hand and hopefully it will be something minor.I'll sart with the minor stuff first and work my was up to the carb and pumps.<br /><br />Seems like a vaporlock problem would be too easy.

 

[karayj]

Re: New engine problems!!!!!!!

I had the same exact problem a used distb from ebay fixed it Replace cap rotor and module you will be all set My boat did the same thing after replacing the engine trust me on this it was not the gas it was not a vapor lock it was not the throttle switch

 

[rogerwa]

Re: New engine problems!!!!!!!

Just a thought. If you sunk the boat, might you have some water in the tank that sloshes to the pickup when taking off?? Do you have a separator?