Hard to start and won't idle

[nckb]

First of all this forum has been a huge help. I have one running but can't quite get the second.

Problem is the 96 GTS with 587. I replaced fuel lines, cleaned selector,cleaned filter, rebuilt carb (including needle), drained fuel, filled tank, new plugs. Engine cranks and cranks and finally fires. Once running it only runs about 5-10 seconds and dies. I can almost convince myself that the rpm surges right before it dies. So it looks lack of fuel, but I seem to have fuel in the lines when I pull them.

I have not been to the water yet, going this weekend.

 

[jhjesse]

When you rebuilt the carbs did you set the pop off pressure, as well as checking the leak down pressure?
If they are set correctly then screw the low speed adjuster out 1/2 turn and see what it does.

 

[mikidymac]

Cranking compression?

 

[nckb]

Compression is 140 ish. I did set the pop off pressure at 32. I did not know leak down was a specific test, but I have enough experience with getting things to seal that I did pump up the completed carb to 10 psi or so to make sure it held.

Will try the low setting out half a turn and report back on Saturday. Loading up to go to the water tonight.

 

[jhjesse]

If you are holding 10psi on the needle and seat with no bubbles, then you are probably good. I am not sure what the specific numbers on 587 carbs are.

I recently had a couple carbs that everything was set perfectly but wouldn't Idle/hard to start. screwed the LSA's out 1/2 turn and solved the problem. Only did minor adjustments after that.

 

[nckb]

Dumb new guy question- which side of the carb is the LSA on? They are marked, which is how I got them initially set. But now that they are under the intake I can remember which one is which.

 

[jhjesse]

Lows are down by the base of the carb. Highs are up higher.

 

[nckb]

Ok. Fiddled with all that and now I am convinced that I am not getting fuel. Pulled the return line off and no fuel comes out while cranking. Supply line seems dry too. I blew through both and there was no resistance. Any suggestions before I assume I messed up on the carb assembly and take it back apart?

 

[soccerdad]

Are you sure you have a good supply from the tank to the carb? It could be a supply side issue before the pump. Is the water separator staying full? Any vacuum leak on the supply side will keep you from getting fuel reliably. That pump has to suck the gas a long way through an obstacle course. You can try feeding to the fuel pump inlet hose with a small tank or bottle. That takes all the other hoses out of the equation. I would do that before I tore into the cabs again.

 

[nckb]

Thanks soccerdad. I was able to get it running. As near as I can tell it was just a matter of getting the whole system primed. Ran good for about an hour or so. But then it got to the point where it would not come off idle even at full throttle. Taking on lots of water too.

 

[nckb]

This is killing me. Now the idle is really rough and it looks like the engine compartment is full of exhaust. Hardly runs at all. Guess I have more to look at in the morning.

 

[jammin777]

with the smoke and water leak i would ck exhaust gaskets and make sure the pipe and manifold is lined up and tight or could be a bad exhaust gasket. also the welded welch plugs on the pipe could be rotted and have a hole. the engine compartment being full of exhaust smoke will cause it to run rough as it is lacking oxygen.

 

[nckb]

All fixed. The large coupling between the exhaust and conical section had popped loose. Still hard to start cold, but when it runs it RUNS!

What is amusing is that I am spending the weekend with family and there are a couple GTI-SE 4tec machines, but there is almost some fighting over my old two strokes.

 

[nckb]

Just wanted to follow up on this. Solved the starting problem. It was the fuel selector/valve. When set to "run" it would suck air in, but not always. Would run without a hitch set on reserve.