[Wassup350]

I bought a 1992 indy 500 engine for my xcr 440. It has the xcr exhaust and carburetors (34 mm) on it. The engine was an efi model so i had to put a fitting on the engine that lead to the fuel pump. What it does, is it'll run fine then at WOT it will start bogging down after a little bit. Real bad though then it runs like crap. I don't get it because it runs good for a while then cuts out. The jetting must be good because the spark plugs are a perfect dark tan color. My thought is that the fuel line is too big that goes from the fuel pump to engine. I could only get a 1/2 inch line to fit on the fitting. I think maybe i could get a 1/4 inch line to fit on it and i think maybe thats what i need to do. I'd be very greatful for any advice.

 

[1000ml]

when the engine bogs and you check the plugs they are dry right?have you tried to open the choke a little at a time when it starts bogging ? if this fixes it you are too lean. does it run good if you hold it at say 3/4 for a long time? you could try a amaller pulse line but i dont think that is the problem.i have heard of people using the wrong hose however and it will collapse under load ie full throttle. i would try to run it at wot and when it starts to run like crap shut it down then drain a carb into a jar and see how much fuel you get out.then compare that to how much you get out when it runs good. may bee fuel pump not supplying enough fuel to carbs

 

[Wassup350]

Thanks a lot!!! That does make a lot of sense. I think the pulse line may not be strong enough and like you said its collapsing and not getting enough fuel. Because it happens at WOT and it actually runs wicked good for a while then it starts cutting out. Which i think now is due to the line collapsing. The plugs were perfectly tan too so i know its not the jetting.