"83 EZGO Fuel delivery issue
 

I have an '83 Marathon with the 244cc Robin engine. It had a cracked case when the starter/generator mounted to the case. I was able to locate a used engine that had a bad jug and piston and this past weekend, I swapped my "good" jug and piston over to the other engine. I now have no fuel at the carb. It appears that the fuel pump works on crankcase vacuum/pressure?? I've got good compression and spark but it won't run. I swapped both the carb and the fuel pump to be sure since I know it ran before the jug and piston swap. Any suggestions as to what I should look for? Is a low pressure electric pump a viable solution? Thanks in advance.

Re: "83 EZGO Fuel delivery issue
 

Hello Motorman and welcome to the forum. Your problem could be several issues but it is most likely that your donor crankcase had worn seals. This prevents the crankcase from oscillation between vacuum and pressure and prevents the fuel pump from working. (Incidentally the compression as measured at the spark plug orifice has no bearing on the crankcase pressure). Unfortunately an electric pump will have no effect as the crankcase oscillations are also needed to suck fuel from the carburetor and then transfer it from the crankcase to the cylinder.
You cannot get to the front seal as the flywheel is in the way but the rear seal is accessible so you could try getting someone to crank the engine whilst you sprayed the seal with WD40. If it tries to start or even starts you have found your culprit. Safety warning. Get the back end on axle stands or remove the drive belt. Watch you fingers in there.

Dave

Re: "83 EZGO Fuel delivery issue
 

Dave,

Thanks for the quick reply. The drive belt is already off but thanks for the warning! I will try lubricating the seals. I should disclose that I reused the old gasket between the jug and the crankcase. I am now thinking that could be an issue?? Thanks again and thanks for the welcome.

Re: "83 EZGO Fuel delivery issue
 

Just to clarify when I said seals I meant to say "crankshaft seals". These are the usual suspects although any crankcase leak will prevent the engine from running. Also the purpose of spraying WD40 on the crankshaft seals is to temporarily close the air gap caused by the worn rubber seal and thus diagnose a bad seal. The only viable repair is to replace both seals (if that is indeed the problem). Sorry if I was insufficiently verbose.

Dave

Re: "83 EZGO Fuel delivery issue
 

I understood what you meant...no problem. Do you think it could be the re-used gasket mentioned above? Thanks.

Re: "83 EZGO Fuel delivery issue
 

Anything is possible but I suspect not. There is a large mating surface there and as long as you torqued it down correctly you should be good. I would get under the cart and look carefully with a flash light at the crankcase / cylinder joint to see if there are any obvious leaks.

Dave

Re: "83 EZGO Fuel delivery issue
 

Thanks, I hope to get to it this weekend.

Re: "83 EZGO Fuel delivery issue
 

Not that any of you were hanging around wondering but I haven't gotten to this yet. I have all my parts so maybe this weekend........

Re: "83 EZGO Fuel delivery issue
 

Re: "83 EZGO Fuel delivery issue
 

With the piston and cylinder change you did get the piston in right? hole on the intake side. Quick check remove the exh pipe run the piston through and make sure you don't see a port if you do OPPS!! just thinking. Hope it's just the seals we've all been there. Keep us posted.