1972 9.5hp Johnson PROBLEM

B_Mc

The problem I have is when the motor is under load it does not run good at all. The strange thing is when the motor is ran in a barrel it runs great. The carb has been rebuilt along with the fuel pump. points have been set and compression is fine. any ideas on what the problem might be would be highly appreciated. thanks

bigoutside

By "not running good" what do you mean?

Chief Shaway

Crack in the head gasket. When running at idle it'll be fine. Under load, the crack opens and compression loss.

bigbill0910

Is the fuel filter in the bowl new? They are better replaced than cleaned.(At least when I wore out my '57 model.)

dcso3009

Could also be a carb needle or gasket. That is what my old Merc did.

Outboarder

i think thats a good point. also, in case you dont know where to buy a new motor, try this shop www.mcmarine.net. really good parts and very fast. if you cant find what you need contact them, they are really friendly people. www.mcmarine.net

cheers, bob

catman50plus

2 things to consider.... The carb must be adjusted for idle, while the motor is IN gear, not neutral. The other would be since gasoline is abrasive, and you did not say if it was at idle or high speed, the high speed orifice may be worn, and if that is the case, the motor will not transition from idle to high speed....