Logo
FULL SITE MENU

Hard Start - Is inline fuel check valve a good solution?

A

ameginnis

New member
Hello,

I have a 1978 Carver with twin Crusader 220's in it. Whenever the level in my port fuel tank gets more than about 10 gallons from the top, the port engine is near impossible to start. (have to pull the deck plate and use starter fluid). Once it kicks over it runs fine and restarts without a problem for that day. If I come back a day or two later it will not start again. The other engine has no issues like this. My guess is that the fuel is draining back into the tank and mechanical fuel pump can not get fuel to the carb at cranking speeds. I thought the most easy solution would be to put a check valve in fuel line at the connection to the carburetor. Is this a good or bad idea?

Thank you in advance for your advice,

Alan
 
Ayuh,..... I's sooner think one of two things, or possibly both,......

Is the carb leakin' off, internally into the intake manifold, as with an empty carb, it takes some crankin' to refill the carb,.....
And / or, the dip-tube in that tank is cracked, causin' the fuel pump to suck air, with the fuel, as the tank's level gets lower,.....

As for a check valve,.... By law, gas tanks are supposed to have an anti-siphon valve at it's outlet, which is in fact a check-valve,....
 
The carburetor has something called a "float bowl" that is presumed to be full of gas up to the level that the float allows. This reservoir is what the engine uses to start up. No fuel flows until after the engine starts, so there is no gas coming from the tank during startup. You probably have some issue with the carb that is allowing the bowl to drain or evaporate the fuel while at rest. I don't know what carburetor you have on there, but some have a drain screw for the float bowl with either a copper or fiber washer. This is a possibility to inspect. You might see evidence of fuel leakage such as discoloration or a clean spot where there is grime elsewhere around.
 
Last edited:
bondo ,

[URL="http://www.marineengine.com/boat-forum/member.php?42677-o2batsea"]o2batsea,[/URL]
Thank you for your suggestions. I will have to see if I can figure out how to access the fuel dip tube and check that out. But not sure how the engine could run perfectly at lower fuel levels if it was sucking so much air that the engine will not start.

I had the carb on this motor rebuilt to try to address this issue. I will look at it to see if I can see anything that looks suspicious though. The guy that rebuilt the carb said something about that it did not have some check valve in it when he rebuilt it so he did not put one back in (he is an automotive guy, not a marine guy and he thought it may have been taken out on purpose.) I can ask him if this could have anything to do with the bowl draining or evaporating. How do you think the potential issue you describe could have anything related to how much fuel is in the tank? I am not following that. It seems like the bowl draining would be a problem regardless. Perhaps a compounding issue though. Any other thoughts?

Thanks Again for the Assistance,

Alan
 
he should have Quadrajets on it. Swapping carbs between the engines will tell if the problem goes with the carb or not.

I'd be inclined to change both anti-syphon valves given the age of the boat (and no other maintenance history).

and 2X on the dip tube being a likely suspect for a fuel level related issue...
 
o2batsea,

Thank you for the ideas. I know the guy that rebuilt the carb for me (trying to address this problem) said that he left some sort of non-return valve out because the card did not have one in it when took it apart (he is automotive guy not boat guy). The thought it may have not been in there on purpose. I have thought this could be the issue, but I thought the non-return valve went to the fuel line. Upon talking to him, he confirms that the piece he left out would cause the bowl to drain. So, I will try correcting that and see what happens. but wont be until the spring. tanks are full now and I will not run enough to empty the tanks far enough until spring.
 
Back
Top