Throttle adjustment question

[MBJJ2369]

Hello everyone,

I have a 1991 Johnson 48SPL J48ESLEIM. I took it out for the first time today. It starts up really easy, idles great and will also fast idle real well too. After cranking it up and letting it idle for 10 minutes or so, I pulled the shift lever out for the fast idle and moved it 80% percent of the way and the motor screamed like it should. When I put it in gear, and give it full throttle it only sounds like it is running at 1/4 to 1/2 throttle and will only go about 7 mph.I do not have a tach for it, (ordered a tiny tach). What does seem odd, is the amount of distance I have to move the throttle lever before it starts to increase the rpms. When I move the throttle lever from the neutral position, it moves a little putting the motor in gear. I have to then continue to move the throttle lever to more than half way before it revs up the engine.

Any ideas?

 

[MBJJ2369]

I just did some checking on the motor, compression in #1 cylinder 130 #2 125, both plug wires jump a 1/2 gap.

 

[Silvertip]

Probably a good idea to remove the engine cover and see what's happening at the engine when the throttle is advanced. I suspect incorrect cable adjustment and/or improper link & sync adjustment. No -- I'm not going to type the procedure as it is quite long. A "Service Manual" for your engine provides the detail you need. And when you get that manual, start at the beginning of the procedure or you still won't have it right if begin halfway through it.

 

[MBJJ2369]

Thanks, I will try that. I have a manual.

 

[oldboat1]

offhand, would guess throttle cable adjustment, based on your description. Standard check is to pull off the remote cable at the engine, and test throttle operation with the engine lever/linkage. If that checks out OK, reattach the cable to match the engine setting(s). Check to see if the cable has come detached from its anchor point at the engine.