gx390 questions... help

35thls1ss19

I got my gx390 conversion running and its great! Drives great. Im trying to work out the last kinks. The problem I have had from the begging is my starter gen does not want to start the motor. I have checked valve lash over and over played with it differently like sho said. It starts it but will take a sec or so before it will turn over. Is this normal? Could it be a solenoid, bad starter? I have a .50 cut head, 8% timing advance.

Second is a new problem. When I first try to start the motor I get a puff out the exhaust before it starts. What does this mean? It hasn't done it till this weekend. Ive re adj valves again and still does it. But once running its fine. Something I should worry about?

Thanks for the help guys!

BGW

__________________
This advertising will not be shown in this way to registered members.
Register your free account today and become a member on Buggies Gone Wild Golf Cart Forum

Streetbu

Hmm, no reason a stock starter/generator shouldn't be able to easily spin athat engine right over if the compression release is working OK. How does it pull using the recoil? If it pulls easily with the recoil I'd look into your connections and battery first.

TheGDFP

With a mild cam, increased compression and advanced timing, the stock compression release may not bleed off enough.

You can grind it to open the valve a bit more.

I installed a Harley electric version of the chainsaw button compression releases, that operates with the starter solenoid.

35thls1ss19

how does the stock compression release work? I will look into pull starting it but I haven't tried it yet. Any other suggestions? ever since I got the motor running it has been like this. can the starter gen be going?

35thls1ss19

the starter struggles for a second or so but once it gets the motor turning over it does fine. is this normal? or should it turn it over the second I hit the gas pedal like the stock motor did?

TheGDFP

It's fighting the added compression. S/G isn't all that powerful, so it has to struggle to roll past TDC. Compression release bumps the valve open, part way through compression stroke, but not far. Set lash on the snug side of clearances.

TheGDFP

sho305

I have a .050 cut and 4 degree key, it would balk a little. Have to make sure your belt is tight and all cables have good connections. Watch it with the seat up if it turns then stops at compression then turns and gets going its the timing/compression doing it. You can cheat and put a kill switch on it and hold it on until it gets spinning. You could run a 4 degree key. First set the lash tight on the valve that does the comp release that helps. It might help to richen the idle if you have not done that already, or it might not but sometimes it does. When I put 1.3 ratio rockers on it helped a fair amount, guess I got 30% more release. When hot mine would stop and squeal the belt when starting, it does not anymore. With a 8 degree key it would be worse. Mine starts just like stock now, before the rockers it would cold but not hot.

35thls1ss19

my belt is tight but the starter does not spin. I also found out my cart was in a flood before I got it. Wondering if water got in the starter and its not working as good as it should? I don't want to spend the money on a new starter if that's not it? I did a compression check and its only saying 80ish. So I assume compression release is working? Only thing I haven't tried is pulling it by hand I need to put a pull cord on it.

slonomo

I had the same problem and I bought a bigger battery and replaced the cables with larger gauge, worked great. Remember, big battery/big cables. I think the one I used was a 950 cca and the old one was 550 cca. Made a diff for me.

If you are getting power to the starter/gen and it's not spinning, it's likely shot. If it was in a flood....well.... Try taking the belt off and running it. If it runs, maybe it needs more power?

Puff out the exhaust? That's usually timing. How short is your exhaust pipe? And do you have a real muffler? Sometimes with a free flowing and short pipe the engines will backfire. Race bikes do it all the time. Something with the oxygen getting sucked back into the cylinder, but usually that's while it's running. A pop at startup is usually timing.