why want it rev high?

[crazyhunter]

i have a 90s model mercury 40hp classic 4cyl. i have had it for about a year and ran it tons of times and never had any kind of problems. the motor hasent sat but maybe 3 to 4 weeks at a time without being ran. i keep it in a basement so it isnt out in the weather. i went out in it sunday to do a little bass fishing and it ran like a champ out to my spot. we fished for probably 2 hours then moved and the motor bogged a little when i took off then ran like it normaly does. well after about 3 more hours we fired up to come back to the ramp and it idled fine and ran good all the way till about 10 mph idk rpms the gauge is messed up but anyway after about 10 mph it just bogged and wouldnt go any faster normaly fully loaded it will do 30. could this be a high speed jet stoped up? i know the carbs are getting fuel i looked at the fillter and could see it going through i also had my friend try to pump the bulb wile i hit the gas it didnt help.

 

[CharlieB]

Re: why want it rev high?

You needs to check spark and compression to determine if your problem is mechanical, electrical, or fuel.

Depending on your findings will determine which direction to proceed.

 

[crazyhunter]

Re: why want it rev high?

spark and compression are good could the maybe be a carb stopped up?

 

[cr2k]

Re: why want it rev high?

Probably.

 

[Mi duckdown]

Re: why want it rev high?

What are the compresion readings. and what is carb stopped up?

 

[aussieflash]

Re: why want it rev high?

Im guessing he means blocked up.Check and clean carbs...if never done before rebuild with new kit....cant hurt.Also check stator as per your engine procedure.Will need Meter/DVA etc.