Lower RPMs after tune up...why????

[32251]

OK here is why I tuned up the little 5hp. At WOT it was cutting out, like flipping a switch at random..would run fine for a bit and then it felt like some kind of electrical short that would cut to about half power..then jump back to full power. So I replaced the points, condensers and coils and wire.

Now it runs smooth as can be, no cutting out...only it feels like it is running at about 65% power. What in the heck is this all about????

Any suggestions.

 

[tashasdaddy]

Re: Lower RPMs after tune up...why????

could be carbs, or link n sinc. is the carb butterly going all the way to horizonal? are you sure it is firing on both cylinders.

 

[32251]

Re: Lower RPMs after tune up...why????

could be carbs, or link n sinc. is the carb butterly going all the way to horizonal? are you sure it is firing on both cylinders.

Sir you have diagnosed my motor correctly!! I found my little pen looking spark plug wire checker and one of the plugs is indeed not firing. This after a full tune up! Will report back when I open her up again and see what I missed.

 

[32251]

Re: Lower RPMs after tune up...why????

OK she is firing on both cylinders!!!!

Please don't laugh at the newbie here as this is my first motor tune up. I thought I would start on my smallest motor in need which was the 5HP Johnson thinking it would be simple...well it was straight ahead, but I made a mistake in setting the point gap. I just assumed that you just put the point cam on the high mark on the shaft and then you adjusted BOTH sets of points.....NOT!!!

When I pulled off the flywheel, the point cam for the plug that was not firing was EXACTLY at the correct place on the shaft! Like the motor muse did this for me to show me my mistake. The point gap was HUGE! No way any fire could jump across it. I gapped it to .020 and put it all back together and it runs fine. I will test it at the lake this week. Now I need to figure out how to get to the pesky right nut that holds the carb on. I can get to the left one, but not the right. I have a kit to rebuild the carb, but I might hold off if the engine runs fine. I can see that there are tool marks on the carb, and there is a nice new looking gasket showing around the carb body and a new fuel line installed. I am hoping that sometime recently it had a gasket kit done.