RPM changes when decarbing

[michaelsen]

When decarbing my Merc 115 6 inline yesterday I noticed something odd. Whenever I sprayed the stuff in the lower or the middle carburetor the RPM increased, but when I sprayed in the top carburetor the RPM's decreased.<br />It don't make sense Why would there be any difference?

 

[Franki]

Re: RPM changes when decarbing

I had a similiar thing, in my case it was one of the lower cyl..<br /><br />It turned out that that cyl wasnt' firing.. and compressing the decarb stuff slowed the motor down..<br /><br />I had a carb blockage, and that cyl wasn't getting much in the way of fuel.. <br /><br />once I had that sussed, things got alot more normal..<br /><br />maybe you have a similiar issue???<br /><br />regards<br /><br />frank