1976 Johnson 70 HP motor (need TSB)

[30yrnavy]

Hello,

I'm new to the forum and thought I would seek the assistance of someone in the know. I recently purchased a 1976 Glastron T-156 with the 1976 Johnson 70 HP motor. I haven't had it in the water yet and am presently in the middle of replacing the flooring (I'm still trying to convince myself that I purchased the boat cheap enough to justify the work and expense of this job...and I hate it when my wife looks at me the way she does). I read a post that there was a TSB on the motor which requires repairs to the carburetors to eliminate mid-range bogging of the motor. I understand the TSB also explains how to tell if the carburetors have already had the mod performed. If anyone has knowledge of the TSB and/or has a copy of it that they could PM to me I would really appreciate it. I'm hoping my motor already had the mod performed, but if not, maybe it's something I could get done sometime during this winter. Thanks.

 

[clanton]

Re: 1976 Johnson 70 HP motor (need TSB)

That information is in one of the Clymer outboard manuals.

 

[Faztbullet]

Re: 1976 Johnson 70 HP motor (need TSB)

That SB is for the mid 80's motor and there was quite a few. The one I think your asking about has to do with rejetting #2 cyinder and idle jetting but the 1976 was not effected to my knowledge....

 

[eavega]

Re: 1976 Johnson 70 HP motor (need TSB)

It was Johnson TSB 1144, issued in September of 1976, which dealt specifically with the 1976 70 and 75 HP motors having an issue with lean condition during mid-range acceleration. If you have one of these motors, the way to tell if the carburetors were already modified is if there is an "X" stamped at the top of the carb body. Another easy way to tell is to look at the idle orifice. The modification called for changing the idle orifice from the .030 it came with to .032. If your carbs have the .032 orifice, then its been modified. Note that the change in the idle orifice is one of many modifications that needed to be made to the carburetor, so don't just change the idle jet and expect it to run better.

For the record, I did the modification following a problem with mid-range acceleration. The situation got better, but it turned out to be one piece of the puzzle. I also had a weak fuel pump (which has since been replaced) and somewhat weak spark due to a failing power pack (which has also since been replaced). Make sure that your engine is indeed running poorly and all other causes are eliminated before taking up the expense and trouble of doing the carb modifications outlined in the TSB. You could end up junking your carbs if done wrong.

Rgds

 

[Faztbullet]

Re: 1976 Johnson 70 HP motor (need TSB)

Thanks for clearing that up, had almost right info just wrong year. Dang its hard to try to remember anything when you get 50!!!

 

[30yrnavy]

Re: 1976 Johnson 70 HP motor (need TSB)

eavega was kind enough to provide me a copy of the TSB in case I need to tear into the carbs. I'll wait until next spring when I can get the boat out on the water and try out the motor. I'll stick with the old saying "if it's not broke, don't fix it." In the meantime, I'll be busy replacing the flooring.

 

[cavey1955]

[h=1]evinrude service bulletin #1144 for 1976 70HP evinrude. need it[/h]

 

[GA_Boater]

[h=1]evinrude service bulletin #1144 for 1976 70HP evinrude. need it[/h]

Well hello to you, too. :facepalm:

Closed due to a post in an ancient thread.