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Old 05-26-2010, 05:49 PM
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Question budsmeng

working on a 1987 Johnson 225hp. mod j225tlcu did compression check and the ranged from 75 -90 psi. I have replaced head gaskets and had heads surfaced. compression after this was 85-90psi. took all carburetors off and cleaned,no dirt in any of the jets and bowls were clean. cleaned grounds on coils and replace bad spark plug wires. pulled flywheel and cleaned grease that was on trigger so it would move easy. i have index flywheel and all cylinders are firing when and i check each cylinder, no double firing. i have done all ohm and output checks. set idle timing and w o t timing. took boat out for test run. boat get up up on a plane around 5500 rpms and ran about 500 yards and dropped to 4000 rpms. hooked timing light to each cylinder ran boat to see if any where breaking down. all ok. checked fuel pressure and it was 4psi at idle. we hook up a 6gal fuel tank and same problem happened again, but did take longer to occur. it dose have a fuel water separator and there is no water in the filter. this year engine does not have the s l o w system. H E L P!!!!!!!!!:
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Old 05-28-2010, 09:14 AM
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Sounds like starving for fuel, try pumping primer bulb to see if brings rpm's back, may need to reclean carbs, check fuel hoses and fittings.
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Old 05-28-2010, 01:05 PM
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Default budsmeng

we did pump up bulb when engine dropped in rpms. we even put ele. pump from filter base to engine and still had smae problem with drop in rpm.
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Old 05-31-2010, 12:55 PM
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Check fuel pressure at the point it looses rpm's to see if loose fuel pressure going to carbs.
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