Post some pictures of the engine in gear with the throttle open completely, perhaps someone will spot something…..Take pictures from both sides and from the front of the carb….
Perhaps you can post a video of the engine running on the boat if possible…
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Have you taken the remote throttle lever box apart to see that the gear teeth on the throttle lever are properly orientated on the straight toothed plastic piece on the end of the throttle cable? If it’s a couple teeth off, it won’t advance the cable all the way.
Dave
Hey Dave, everything seems to be in good order inside the remote shift box. I think I may have figured out what the issue was. I think when I rebuilt the carburetor I may have put the
stop adjustment screw that goes on the little rod that goes from throttle rod to the carburetor in the wrong place. Now when I push the remote throttle lever forward to maximum the throttle valve is in the wide open position and seems to stay there. I was going to test it out on the water today but it started raining here. We really need the rain so I can’t complain too much. I’ll let you guys know how it goes when I get it in the water!
I took the boat out yesterday fully convinced that I had the problem taken care of by adjusting the set screw on the little rod that goes from the throttle rod to the carburetor. Unfortunately I still have not solved the problem. I moved the set screw from one end to the other with little to no change in the way the motor ran. I ran the boat for about an hour and pulled the plugs to see what they looked like. The top plug looked good but the bottom plug looked shiny black but not wet. I checked the spark and both plugs were delivering good spark. I checked the compression a couple of days ago and both cylinders were at 120 lbs. Can it be running on only one cylinder if I have good compression and good spark? Should I try running it with the bottom plug wire off and seeing if there is any difference in the way it runs?
Jeffrey,
I know you said you are getting good spark, but have you tried swapping the plugs out with another set?
In the past I have experienced plugs that would “air fire” grounded out against the block but not under
compression when installed in the motor.
Sure, it is totally possible to be running on one cylinder even though it has spark and compression on both…. Like Brooke says, always return to the basics when we get confused, starting with a new set of plugs. Try running the engine with those inline neon spark testers or checking with a timing light while running…Perhaps it is running on two at low speeds, then dropping a cylinder/spark at higher RPMs. Anything most problems are usually simple things we have overlooked.
Easy test to see if it is running on one cylinder. With it running at high idle, pull a plug wire. If it keeps running, put that wire back on and pull the other. The motor WILL run on one cylinder. But if you pull the plug wire on the only one that’s firing then the motor will shut off.
Another option is to put a timing light on the each wire while running.
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