1985 Johnson Sea-Horse 15 hp with fuel problem

[lamarkeiko]

I cannot get the motor to run at full power and rpm. First let me explain my initial problems and what I've done so far.
Last year I only had my boat out one time, and at that time I couldn't get full throttle and rpm. Had no problem starting, and the motor seemed to run fine, but I could get what seemed like only half throttle. At the time, I contributed it to possibly old fuel or maybe needing new plugs. This year I started out with new plugs, and fresh high octane non ethonol gas. I had a real hard time with lots of pulling to even get the motor to fire. When I finaly got the motor to start, I could only keep it running for a few seconds at a time. I kept going back to pump up the fuel line bulb and the motor would start fairly easy, but would only run a few seconds at a time. I figured I may have a bad seal somewhere in my fuel line between the motor and tank. I ended up purchasing a new tank, cut off all connections and redoing each connection on the bulb, fuel line quick connectors and the in-line fuel filter. This also shortened my fuel line by over 2 feet, which I thought may help. Once this was done, the fuel bulb could be pumped up fairly easy. I proceeded to start the motor, and it was able to stay running.
It is back to starting easy, idles good, but only goes to about half power when the throttle is turned all the way up.
This leaves me to think I may have a fuel pump problem, or maybe it is in the carburetor. I see no signs of fuel leaking anywhere. I'd appreciate any help on this. Hopefully I haven't streached this out too much.

Thanks
Lamar

[cookjeremy]

clean the carb and does it bog down at full throttle and run crapy or just sit at one steady rpm.

[Solarman]

I think I would agree. It sounds like trash in the carb bowl blocking high speed jet. Be careful not to change float setting. But a little cleaning, and blowing the passages clear may solve your problems. If you remove any of the adjustable jets, make sure you note what they are set at before you remove them, they have to be adjusted to same setting when reinstalled (count the number of turns closed till lightly seated- reinstall to same number of turns from lightly seated.). If multiple carbs, check each one, and note each, and do not mix up any of the jets, some jets in multiple carbs are different between carbs.

Good luck, post back what you find.

[lamarkeiko]

Thanks for the reply back. I had a suspicion the carb is the culprit.
I'm a little nervos to remove the carb and do some disassembly.
Do I need to have a carb repair kit, or will it be possible to reuse original gaskets?

Lamar

[lamarkeiko]

I have to sheepishly say that I think I have found the problem to not being able to achieve full throttle with my motor.
As I was studying how to remove the carb so I could do a cleaning, I was looking at the cam on the flywheel that pushes against the carb roller. When I twist on the throttle, the cam would hardly move the roller. I started the motor, and took a screwdriver and pushed the roller, and I had all kinds of acceleration.
I got to thinking there may be timing problem with the carburetor throttle linkage. After some studying on leeroys ramblings trying to figure out how to make adjustments, I went back out to look at the motor, and that is where I discovered that there is another cam on the flywheel that hits a stop, preventing you from going to full throttle. This only happens when the motor is out of gear. Put the motor in gear and it looks like I have lots of throttle.
I'm just running the motor in a 35 gal garbage can full of water now. The proof will be when I take it out on the lake.

Lamar

[cookjeremy]

if you where running it in a can and in neutral the first time u posted a problem then yes you have no problem with the motor there is a neutral lock out so u can only rev engine just above idle unless you have it in gear.