GP 88 Evo thread

[Bunky.F.Knuckle]

You chose the right guy for service! Joe is the man! He built an engine for me a few years back, and it is a monster! Plus, he is somewhat local to me.

He made the fix for the 123 fuel delivery problems. He made that engine what it is today.

 

[Jetpainter]

You chose the right guy for service! Joe is the man! He built an engine for me a few years back, and it is a monster! Plus, he is somewhat local to me.

He made the fix for the 123 fuel delivery problems. He made that engine what it is today.

I need to send him my GP61 and see if he can get it ironed out. Performance is great, idle is great, low and smooth, transition is awesome, but the first start of the day is miserable. I think it was 20+ flips with the choke on today before it popped. And when it's hot and humid that really sucks.

 

[Bunky.F.Knuckle]

I need to send him my GP61 and see if he can get it ironed out. Performance is great, idle is great, low and smooth, transition is awesome, but the first start of the day is miserable. I think it was 20+ flips with the choke on today before it popped. And when it's hot and humid that really sucks.

Are you lean on the L needle?

 

[Jetpainter]

Are you lean on the L needle?

I could try richening it some, but it's at 2 3/8 now, and the transition is nice and crisp with no sign of being lean. That being said I really shouldn't have to be that far out on the low, but it's needed to be that way since new. I went through the carb two weeks ago, and everything seems good. I tried starting over at 1 1/2 on both, but it was so lean on the low that it would idle, but take no throttle. By the time I had good transition it was at 2 3/8.

 

[Bunky.F.Knuckle]

Should call him first, and see if it is something he can help you with first, via phone. Could be a clogged jet or passage.

I agree, that the L needle shouldn't be out over 2 turns.

 

[49dimes]

I could try richening it some, but it's at 2 3/8 now, and the transition is nice and crisp with no sign of being lean. That being said I really shouldn't have to be that far out on the low, but it's needed to be that way since new. I went through the carb two weeks ago, and everything seems good. I tried starting over at 1 1/2 on both, but it was so lean on the low that it would idle, but take no throttle. By the time I had good transition it was at 2 3/8.

If it is not a restriction then the metering plunger spring may be too stiff or the fulcrum is bent. If your out that far on the low your not metering a sufficient "volume" of fuel to the underside of the diaphragm me thinks.

 

[Jetpainter]

If it is not a restriction then the metering plunger spring may be too stiff or the fulcrum is bent. If your out that far on the low your not metering a sufficient "volume" of fuel to the underside of the diaphragm me thinks.

The stiffness of the spring I can't be sure of, but the fulcrum is at the correct height. I checked it when I had it apart. I also ran carb cleaner through everything and the three idle ports into the throat were flowing well, as was everything else as far as I could see.

 

[49dimes]

May be your funny bone was not feeling it so I edited and my apologies. Maybe just swapping the carb out will let you get closer to regular settings. Or just keep running it. It sounds as if it is running good.

 

[49dimes]

Just a thought since I believe you do have a fuel volume issue......Small air leaks, carb pump just not getting it done, partial blockage of the pulse port are things I would check or look for.

 

[Jetpainter]

May be your funny bone was not feeling it so I edited and my apologies. .

It's all good!

Just a thought since I believe you do have a fuel volume issue......Small air leaks, carb pump just not getting it done, partial blockage of the pulse port are things I would check or look for.

I checked it all when I had it apart. There seems to be good seal on the carb to the aluminum adapter and to the reed block then engine. I checked the pulse line since I changed it to be able to flip the carb 180 to make the linkages work out when I first installed it. I wanted to make sure it wasn't kinked or pinched and all seems well. I even blew through it.

I'll get a hold of Joe when things slow up here at work later in the week and see what he thinks.