Loss of RPM

[atom2000]

A friend of mine has a johson 1998 70 Hp carburettor.The problem is that after about 15 to 20 min (after starting the engine from cold ) the engine revs drop down to 2500 and wont exceed this until the engine has cooled down about 2 hrs or the next day. He has got someone to check the carbs and had the stator changed.But the problem still persists.
I adviced that most probable the problem lies in the power pack (slow being activated)or the temp unit (the engine is not overheating according to him). 1. would I be correct or should I check something else.
2. if so how can i check the power pack /temp gauge.
Regards

 

[tashasdaddy]

Re: Loss of RPM

motor is running hot, that is a safety mechanism, that cuts the rpms, to 2500, to keep from ruining the motor. change the impeller, check the tstat for proper operation.

 

[HighTrim]

Re: Loss of RPM

ENGINE WILL NOT ACCELERATE BEYOND 2500 RPM:

1. Use a temperature probe and verify that the engine is not overheating.
2. Disconnect the tan temperature wire from the pack and retest. If the engine now performs properly, replace the temperature switch.
3. Make sure the tan temperature switch wire is not located next to a spark plug wire.

 

[atom2000]

Re: Loss of RPM

thanks I will tell him to check them