657 runs good for 10 minuets then

[Lhardy]

All right last time I posted was able to get good answers. I’ve been messaging Matt on here and he’s got good ideas but I’m just running out of options and can’t figure it out.
So I can get it off the trailer and runs great even @ WOT for around 5 to 10 minutes.
Then it starts running out of power to me it’s like it’s bogging/not getting past ideal.


My current set up is a 94 SPX with the 657 .

Of course all fuel lines have been changed.

New fuel filter.

New battery.

New rectifier. (At first I thought this was the problem)

Carburetors just got rebuilt.

Compressions in the high 140s.

Engine is cooling properly.

if you guys need anymore info let Me know

 

[Lhardy]

By the way I’ve done this 4-5 times now so after it cools down or the next day it’ll run great again for 5 or 10 minutes and then starts acting up.

 

[Bdk1282s]

I have the same problem 95 speedster , ground/electrical nightmare , it failed me again today. I'm going to run new grounds , another new battery , and have to replace a stripped terminal in mpem control box . Every connection keeps vibrating loose , very frusterating.

 

[Lhardy]

Maybe more people will reply see what’s going on.

Very interesting and thanks for your input