1991 Johnson 40 hp 2-stroke bogging

[Otis K]

Hey guys, new to the forum. Unfortunately i was kind of forced here because i am stumped on my engine i just now bought.

My 1991 Johnson 40 hp 2-stroke will not run past 2000 rpm. It starts up, idles, & even cruises great up until just before half throttle and bogs down. However, if i push the Key in activating the electric Primer it will plane the boat and run perfectly at full throttle, but will bog right down the second i stop pushing the key and the problem remains.

The one thing i have personally noticed when looking inside the Carb Bores is that the Bottom Carb is barely shooting any gas into the manifold compared to top Carb at full throttle



Here is everything i have done to it up to this very point:

Tested Compression: 120 psi Top Cylinder & 125 psi Bottom Cylinder

Replaced the Floats

Cleaned all the jets thoroughly including the Main jets with a steel wire and soaked everything in Carb Cleaner.

New Fuel, Premium unleaded

New Sparkplugs


Could it possibly need new Reeds?

I will keep you guys all posted until the motor is running. I want to get into the ocean for some halibut before winter comes. So please help.

 

[Otis K]

Nobody wants to help me figure out this old peace of crap Johnson i figure. Yeah, i don't blame.

Figured some of you must of encountered this problem once upon a time. Bottom carb isnt delivering fuel, even after cleaning.

 

[Otis K]

****Problem solved***

The main Jet tube in the center of the Carb that enters the Carb bowl was missing the Star-holed gasket! The prior owner must of failed to replace it when they rebuilt the Carb leading to the problem i just experienced.

So if anyone trying to google answers for the same problem be sure you are not missing it! The star-holed gasket that slides around the main jet tube is a must or the boat will not run above 2000 rpms. I was stumped and did a bunch of needless work.

Thanks, i hope this ends up helping others. Be Safe on the water.