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Force 25 L engine stuck in high revs

Old 04-19-2014, 06:36 AM
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Default Force 25 L engine stuck in high revs

Hi All,

I have a problem with this engine. The car was not used in over a year, and I could some evidence of rust on the black steel internal parts. I have completely stripped, cleaned and polished the engine. Where necessary on the piston sleeve and piston head, I used a 600grit wet dry paper followed by polishing with very fine polishes.

two problems - the car is very hard to start, and the settings for the MNV a SNL are way off their factory settings. Normally I have to inject some fuel directly into the carb.


Main problem - I can get the engine to idle and rev up and down reasonably well up to about 50% throttle. However if I go above that, the engine starts running as if's on full throttle, even though the air gap in the carb is back to a nominal meeting (nominal 1mm), I thought it might be due to an air leak due to the engine reassembly, but all seems good.


It's driving me nuts this one - any ideas anyone? Would be much obliged if so.

james100abc
Old 04-28-2014, 06:02 AM
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moved to the car forum.
Old 04-28-2014, 07:19 AM
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Using sandpaper of any kind on an ABC sleeve and piston probably ruined it or greatly reduced its lifespan. Anytime the engine revs really high when the throttle is closed indicates an air leak of some kind. I'd be backing the main needle and idle needle out a full turn from wherever they are now and drive the car to reset the needles. Set the main needle for fastest top speed without sagging and Richen 1/16-1/8 turn then set idle mixture for a clean transition from idle to WOT after idling steady for 10-20 seconds in that order. If you cannot attain good needle settings using this method then something is wrong mechanically. The car must be driven to set the needles with a good WOT run between adjustments and only when the engine is hot. Using fuel with at least 15-20% nitro and 10% oil will give reasonable performance. Fuel with more nitro and less oil will give more performance but gives you less of a cushion against a lean run.


Hope this helps some.

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