Newbie needs help with 1986 8hp Johnson

[Aluminum5e]

My 1986 Johnson 8hp J8RCDE blogs down and surges at full throttle but runs fine at half throttle. I pulled the plugs and they were just a little wet. Made sure vent was open at fuel tank. I found a distorted foam gasket between the silencer and the carb. I straightened it out as best I could and reinstalled. Can someone help me with what my next steps should be. Should I Seafoam the carb? Please help - so frustrated. Thank you.

 

[Mohawkmtrs]

When it's bogging and surging, pump (squeeze) the primer bulb. If the problem goes away, check for air entering the fuel line or a defective fuel pump.

If the issue does not go away, remove, disassemble and clean/rebuild the carburetor.

While Seafoam is good, my experience is 50/50...I normally end up removing/cleaning the carburetor.

 

[racerone]

Some will argue.----Some basic trouble shooting needs to be done.---First is a compression test.-----Then a check for strong spark.---Spark must jump a gap of 3/8" or more.-----Is the thermostat in place and working ?----Have you tried to operate the manual pump to see if it will maintain full throttle ?----Checked the O-rings in the hose connecters ?

 

[Scott Danforth]

there is no mechanic in a can. troubleshoot as indicated.

 

[Joe Reeves]

Bogging down when throttle is applied is normally caused by the high speed jet in the lower portion of the carburetor being somewhat clogged due to the sitting periods over time.... clean it.

Let us know if that cures your problem.

 

[boobie]

Agree with Joe. Let us know what happens

 

[spybot]

The 4 gentlemen above this reply have a vast amounts of knowledge in this area.
If i were you i would follow there directions to the letter. If you do i can guarantee with there help you WILL find the cause of the "bogging and surging"
I cant help you as i would only tell you what has already been asked. Compression test & Spark test.
Some may argue over the point i am about to make.
I think Seafoam will NOT help as Scott said "there is no mechanic in a can"
Just go through each step and post the results as you get them.
Hope you get it sorted out