Issue with my 1977 55hp johnson

[RoughFishAssassins]

I recently had the carbs rebuilt then the head gasket. All was running good till I got some weed wrapped around the prop. After that it just doesn't go, it still runs and moves but not like it was. Seems like it only will run about 1/2 throttle when at WOT. But when I take it home and put on the muffs it runs like it should. What might have happend? The prop free spins nice without any wobble. I appreciate the help!

 

[Daviet]

Re: Issue with my 1977 55hp johnson

I would start by checking the spark and compression, if they are OK move on to the fuel delivery system.

 

[RoughFishAssassins]

Re: Issue with my 1977 55hp johnson

?? OK, but why would it run fine with the muffs on but not in the water? I don't see how that would affect it. It only is a problem when in gear in the water. Any explaination or other ideas?

 

[BonairII]

Re: Issue with my 1977 55hp johnson

?? OK, but why would it run fine with the muffs on but not in the water?

There is no backpressure or load while on the muffs

 

[RoughFishAssassins]

Re: Issue with my 1977 55hp johnson

I understand that, but how would this affect the spark, compression or fuel delivery?

Some advice that I got was possibly a bad bearing in the lower unit, could this be a possibility?

 

[EN2]

Re: Issue with my 1977 55hp johnson

You may have lost one of the three thing for proper operation, check spark , compression first, if ok check fuel delivery.

 

[oldrudedude]

Re: Issue with my 1977 55hp johnson

As daviet, bonairII and en2, said anything will sound good running on muffs. No back pressure and no load just freewheeling. Two strokes like that. So now you have to start with the basics: Good compression? Good spark? Good fuel? Do a compression test. What you got? Do you have good spark to all cylinders. All that ok? Now you can move on to good fuel.

 

[RoughFishAssassins]

Re: Issue with my 1977 55hp johnson

Just wanted to say thank you, I finally got to check the motor out and it was a blown head gasket. I think I know when it happened but is there something that would cause this to happen? maybe I can fix something else to prevent it from happening again?