Engine "coughs"

[BluefishBuster]

Hey guys. New to the board here. I just acquired a boat a few months ago with a 2000 2-stroke Johnson 130HP Outboard. Motor has been running great until this past weekend. Now, the motor "coughs" at idle speed and occassionally stalls. Runs like a bat outta hell when wide open. Changed the plugs ... didn't help. I'm thinking fuel filter might be dirty ... don't know the maintenance history on the boat from before I bought it. I don't wanna start messing with the 4 carbs and screw something up. Any thoughts guys?

 

[Cricket Too]

Re: Engine "coughs"

Welcome to the post. I would get some OMC Engine Tuner (Decarb) and run it through a couple of times, run some Seafoam through the gas. If you don't already have a fuel water separator, install one, if you do, replace the filter.

 

[seahorse5]

Re: Engine "coughs"

The service manual tells how to adjust the throttle and carb linkage correctly and how to adjust the carb mixture screws.<br /><br />Also refer to the service manual for checking thermostat operation so the motor is not running too cold, causing your "coughing". <br /><br />Use the Champion QL78YC plugs gapped at .030".

 

[BluefishBuster]

Re: Engine "coughs"

OK, I replaced the fuel filter ... no change. So I pulled the thermostats (vernatherms on this engine). I found small pebbles stuck in the opening where the vernatherm allows water to enter the block. So it looks like the engine temp is not being regulated (open all the time). I haven't put the vernatherm assemblies back in the engine because I have a concern. The little pebbles I found ... there were more inside the motor. I removed all that I could get to with a pair of needle-nosed pliers. My concern is that there are more pebbles in the water jackets. Does anyone know if there is a way to flush out the water jackets of this type of debris? Or should I not be concerned about this? Thanks so much guys!