Won't stay running

[rnds76b]

Have a 5 year old Mercury 7.5 hp outboard that starts (as long as it's fully choked), but won't stay running (regardless of choke position). It's getting good gas (other motors have been run off the same gas and tank) and both spark plugs look OK and were recently cleaned. Am thinking I need to adjust the idle screw, but being a novice to this thought I'd ask first. Any ideas/advice? Thanks in advance.

 

[hkeiner]

Re: Won't stay running

There a lots of possibilities. I suggest that you perform a few troubleshooting tests and report back on your results. This will greatly narrow down the possibilities and you will most likely get better advice as to what to fix.

One simple test is to squeeze the fuel bulb while trying to start the motor. If that helps, then the fuel pump is suspect. Another test is to spray some 50:1 fuel mix into the carb throat and then try to start. If that helps, then the carbs are suspect and probably need cleaning or adjusting. Adjusting the idle screws is also a valid troubleshooting test, just return them to the standard link and sync spec if idle screw adjustments don't help. Of course, checking for a good spark with a spark tester and good compression with a compression gauge are always good basic tests to perform when motors do not run right.