25hp Johnson misfires but idles OK

[2brauns@bellsouth.net]

I just recently purchased a used boat to tinker with and get going. As the title states the motor is a 1975 Johnson 25hp outboard which seems to have some carb troubles.<br /><br />I cleaned out the carb and found some varnish buildup, but have since cleaned it out. The motor starts pretty well, but seems to misfire or pop out the exhaust when at off idle speeds (testing has been limited to garbage can test tank for now). Seems to me there is raw gas getting drawn in to cause the motor to misfire. Or maybe the engine is running too lean. <br /><br />Any other ideas? This is my first two stroke to work on so I'm afraid I may be looking over something obvious. Oh yeah, there are no longer any ignition coils on the side of the motor, so I assume it has been converted to electronic ignition already.<br /><br />Thanks,<br />Jeremy

 

[rabidfish]

Re: 25hp Johnson misfires but idles OK

Get yourself a real Johnson service manual from a dealer. Refer to the section Timing/synchronizing. Make these adjustments just like the book says IN THE ORDER IT SAYS TO DO THEM !! This is critical to make any outboard run correctly. If this doesn't fix the problem, then you need an expert to look at it for you.

 

[corm]

Re: 25hp Johnson misfires but idles OK

Hi Jeremy,<br />Pull the flywheel and set the pts at .020.<br />check the condencers to make sure the screws haven't loosened up.<br /><br />...have fun...corm

 

[2brauns@bellsouth.net]

Re: 25hp Johnson misfires but idles OK

Thanks guys, the motor is running much smoother now.<br /><br />Happy boating,<br />Jeremy