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Under performance under load

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Inkleyc

New member
I have an 87 Supra Ski with the ford windsor 351 in it. Two years ago i started to loose compression so we rebuilt it. It now runs great and the compression is good. When i run it out of the water i get response on RPMs, but when in the water i can only get about 3200 RPMs when i open her up all the way. What could be causing it to preform bad under load?
 
Welcome aboard!

First off, may I suggest just one post vs multiple ones.....

I'd make sure the timing advance is functioning correctly first....
 
Makomark,

We have checked the timing a few times, but I will check it again. Any pointers on making sure its perfect? Also we put a more aggressive Cam in when we rebuilt, would this cause a change in the timing?
Thanks.
 
Ayuh,.... Ya probably got the same problem that burnt the motor down,...

Bad fuel, or Bad fuel flow, causin' a lean condition,....
 
"checking the timing" isn't the same thing as verifying the timing advance.....

And the caution offered by Bondo is due consideration as well...I can't tell you about the cam change driven impacts without knowing the details of the rest of the engine....
 
when i open her up all the way. What could be causing it to preform bad under load?

1) re: more aggressive cam. A marine cam??? Engines in marine applications are "torque" hogs and need cams with broader torque peaks. Not knowing what that new cam does is problematic. You may have shot yourself in the foot with the cam change.

2) Before you lost compression and performance, what WOT RPM did you get? Was the prop changed?

3) re: "loosing compression" what % of maximum WOT RPM did you normally run at.
 
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