I just wanted to pass along some info about an issue I finally solved with this motor. It’s a rather interesting solution.
I bought my used boat last spring and shortly after I got it home I had some issues with the motor dropping a cylinder at rpm above 1500. It was a fairly consistent issue and it became quite difficult to get on plane. The previous owner did warn me that he had this issue before and that replacing the optical sensor would fix it.
I began trouble shooting and discovered which cylinder was failing and continued to replace the plug wires, optical sensor, power pack, spark plugs with no success. I did all of this based on info from google searches. Many of the people with the same issues reported taking it into a mechanic without solving the problem so I decide to keep at it. I spent all last year with this issue and finally gave up in October when I winterized the boat.
This year after I got it out of storage I began searching online again. I came across a forum where many people were having issues with the primer bulb loosing prime and gas leakage from the motor. The root cause was warped float bowls on the carb. It was determined that over tightening the screws on the float bowl were causing warpage and resulting in leakage and in some cases misfiring of the engine.
Well low and behold replacing 3 of the 6 float bowls solved the problem. I’ve put on almost 200 miles on this motor this year and am happy to report not one instance of misfiring. I’ll likely be replacing the other 3 shortly for good measure.
I just thought I’d pass this knowledge along in case someone could use it.
