'89 bayliner omc cobra 5.0L HO dies after a few min

[ironhead8126]

I bought a '89 bayliner with an omc cobra 5.0 HO and the motor runs perfect in idle speed but when i get it planed out it will run fine for about ten min then all of a sudden it will die. I put it back in neutral and hit the key and it will do it again as many times as i will restart it. Will run forever at idle speed but will die at high speeds. I am new to boats all together and there is no one around here that will touch it. I put a new fuel pump on it and a coil and a starter. Maybe you guys can give me some suggestions. Thanks

 

[Vincentgould]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

Fuel filter?

 

[ironhead8126]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

do you mean the fuel water seperator put a new one on it and i am new to all this and dont know where exactly the fuel filter is

 

[Bondo]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

do you mean the fuel water seperator put a new one on it and i am new to all this and dont know where exactly the fuel filter is

Ayuh,... That's the 1,.. was there any Crud in the old 1,..??

 

[Vincentgould]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

The jets in the carb could be clogged.

 

[ironhead8126]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

no filter was clean and the gas in it looked good. Maybe i just need to rebuild the carburator

 

[Blk-n-Blu]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

Might be another filter at the fuel inlet to the carb.

 

[ironhead8126]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

checked that filter too and it was nnice and clean. I pulled off the water pump today to check it and it was fine so i went to the thermostat and pulled the housing and found out that the thermostat is built directly into the housing or is stuck. it was stuck in the closed position so i am thinking that the engine has been running hot making it shut down. The gages on the dash dont work too well so i cant get an accurate temp reading. I pushed the thermostat in and now it is stuck in the open position but i think i might have damged it. I have never seen a thermostat built into the housing so not sure if it is right. No mechanics around here will touch it and I know very lil about it so any help will be appreciated. Thanks guys. Also tested the pressure on the fuel pump today and it it pumping as it should

 

[mcleaves]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

checked that filter too and it was nnice and clean. I pulled off the water pump today to check it and it was fine so i went to the thermostat and pulled the housing and found out that the thermostat is built directly into the housing or is stuck. it was stuck in the closed position so i am thinking that the engine has been running hot making it shut down. The gages on the dash dont work too well so i cant get an accurate temp reading. I pushed the thermostat in and now it is stuck in the open position but i think i might have damged it. I have never seen a thermostat built into the housing so not sure if it is right. No mechanics around here will touch it and I know very lil about it so any help will be appreciated. Thanks guys. Also tested the pressure on the fuel pump today and it it pumping as it should

The thermostat is not built into the housing. It may look that way after a while, but if you dig carefully with a jewelers screwdriver you will find a rubber o-ring is holding it in. It's in a small recessed channel.

Also, you need to get your gauges working ASAP or you are going to have more serious problems to fix than the ones you mentioned. Just some advice

 

[ironhead8126]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

thanks mcleaves, got it out and hoping it will help my problem. I went today and bought a fuel pump and vacuum tester and tested the fuel pump and it is fine but cant figure out exactly where to hook up for the vacuum test. It says test as close to the intake manifold as possible and I have read the adults only section and still lost. I am a total noob to all this. Ordered the manual but will take a few days to get here. Also I want to check the anti siphon and the fuel vent but dont know where they are located. thanks

 

[ironhead8126]

Re: '89 bayliner omc cobra 5.0L HO dies after a few min

thanks all found the problem, it was the anti siphon valve. It had some trrash and stuck took off and ran with brass fitting and ran like it was suppose to. Getting a new valve and problem solved. Thanks for the help