Wont stay IDLE after RUN???

[Aquadzac Captain]

Bayliner 24.5 foot Capri Sundbridge<br />350ci OMC GM MOTOR Crate<br />EDELBROCK 600CFM QUAD JET (Carb Adusted by marine shop.<br />NEW FUEL FILTER<br /><br />Boat ran great until "I thought the old carb Rothenberg went bad. After running the boat 10 minutes at 3000 RPM I dropped it down to NO WAKE speed and it stalls. Hard to start then when it does wont take the low speed cruise and stalls.<br /><br />This year changing to a new carb Edelbrock 600 it still is acting the same way. I beleive it is not the carb but something else I am missing. I changed out the fuel filters and with new lines. If its not the fuel lines or the carbs what could it be? Any one out there had the same issues and resolve??

 

[Mik]

Re: Wont stay IDLE after RUN???

I'd suggest the basic stuff. Check the plugs, wires, distributor for ignition. Run a compression check, make sure they are all about equal. Check the carb idle screws. Could be that while the choke is on, it's getting extra gas, then when the choke opens, it doesn't have the fuel to idle.<br /><br />Mik

 

[SeaSkwurrel]

Re: Wont stay IDLE after RUN???

You might want to check the fuel pump pressure at idle as well.

 

[Aquadzac Captain]

Re: Wont stay IDLE after RUN???

OK, I will go back and add a gauge to the fuel inline to the carb. Will let you know what I see.<br /><br />thanks

 

[Aquadzac Captain]

Re: Wont stay IDLE after RUN???

MAYBE IT!!! I get out in the water and it runs great for a bit then you idle down to troll speed and the motor begins to stall or hard start you may have "VAPOR LOCK". This is when the fuel lines get too hot and the fuel reaches boiling point and vapors into the carb rather then inject gas wet. Thus the motor dies or hard to start at idle. That is until it cools down and then the cycle starts all over. Very rare but can happen. My exposed rubber fuel lines are soo close to the manifold, inline fuel filter touches water hoses, that they are getting a brunt of some heat. Not to mention heat goes into the mechanical fuel pump and filter from the block adding to the fuel heat increase. Right now I am doing a bunch of temp tests before and after a run to see how hot the dog house is and how hot the fuel lines are becoming before and after a run. Next I plan to move all my lines, go elec pump and take the lines away from the motor and have them protected with braid. Its a plan but yet I dont know if it will fix my problem but I have checked every thing and by looking at the design it could be the culprit. Oh one more thing, I have no scoop to push air into my lower dog house (motor housing) thus the ventelation in my motor well is getting way hot. I shoul have been using my blower all along. More to come on one of my posts soon.

 

[Aquadzac Captain]

Re: Wont stay IDLE after RUN???

MAYBE IT!!! I get out in the water and it runs great for a bit then you idle down to troll speed and the motor begins to stall or hard start you may have "VAPOR LOCK". This is when the fuel lines get too hot and the fuel reaches boiling point and vapors into the carb rather then inject gas wet. Thus the motor dies or hard to start at idle. That is until it cools down and then the cycle starts all over. Very rare but can happen. My exposed rubber fuel lines are soo close to the manifold, inline fuel filter touches water hoses, that they are getting a brunt of some heat. Not to mention heat goes into the mechanical fuel pump and filter from the block adding to the fuel heat increase. Right now I am doing a bunch of temp tests before and after a run to see how hot the dog house is and how hot the fuel lines are becoming before and after a run. Next I plan to move all my lines, go elec pump and take the lines away from the motor and have them protected with braid. Its a plan but yet I dont know if it will fix my problem but I have checked every thing and by looking at the design it could be the culprit. Oh one more thing, I have no scoop to push air into my lower dog house (motor housing) thus the ventelation in my motor well is getting way hot. I shoul have been using my blower all along. More to come on one of my posts soon.