Muskyhunter86
New member
I recently purchased a 79 Johnson 9.9 and am having an issue with the throttle linkage. The motor runs great and shows very little use and the only thing I can find wrong with it is in the throttle. It has excellent throttle responce going from idle to WOT, but at WOT, (what I will call the secondary shaft) that links to the tiller handle and goes into the motor housing has approximately 1/2" of slop in it. At WOT, the shaft moves forwards and I lose RPM's, and then it will slide back, and I pick up RPM's. I don't know exactly how many RPM's I'm losing, but I will say I can see a great difference in my speed. (Lowrance HDS 8 Gen2 w/GPS) I will go from 14 MPH to 18.5+ MPH when the shaft is slid back into the motor housing. I am wondering if anyone else has seen this with these motors, and if so, how can it be fixed? I've been through the schematics for the motor, and can't seem to find anything that would help me out other than how to disassemble everything. Also, I was wondering if anyone knows what size and type of hose is used going from the fuel pump to the carb? A friend of mine has a 76 Johnson 9.9 and we replaced his original hose with 1/4" standard rubber fuel hose, and it is too big... Any help and suggestions are greatly appreciated. Thanks.