56 johnson sea horse problems

[zed2500]

Well ya'll i have been trying to figure out what is wrong with this motor for sometime now. It is a 56 7.5hp Johnson Sea Horse. It hasn't been started for about 6 years, so I cleaned out the tank, replaced the fuel lines, rebuilt the carb, and new spark plugs. I can get it to fire up, but two things go wrong.

#1. Once I prime it and get it started, it runs fairly rough for about 30 sec. and then starve out. I thought this was possible the tank loosing its seal, so I rebuilt the tank and still have the same problem.

#2. When the motor is running, i get water coming up into the engine compartment. Is this normal?? I have a 70 6hp Evinrude and it doesn't do this so I am fairly certain it shouldn't do this.

I am not extremely versed on outboards, but am mechanically inclined. I have tried all the obvious stuff. I am hopeful that someone out there can give me some pointers.. thanks for the help......

 

[Mas]

Re: 56 johnson sea horse problems

Do a compression check...might have a blown head gasket. You should not have water there...unless you're getting a lot of spray underway.

MAS

 

[freddyray21]

Re: 56 johnson sea horse problems

a 56 7.5 hp if I remember correctly you have to pull the power head to change the impeller. More than likely the last person to do this did not replace the gasket. Pull the powerhead and look. You can cut a new gasket out of gasket paper or if the old gasket is not too torn up some form a gasket over it will usually seal it up.

Those run off a pressure tank and are very sensitive to air leaks. Of course the obvious is the cap on the tank on tight and is the seal in good shape. If so the next thing I would look at is the O rings in the connector. If they haven't been changed in awhile they are probably the culprit. You can bypass the connector all together by running your lines directly to the air port on the intake and the carb. Make sure you are hooking the right lines up to the right spot. The air line goes to the intake and the fuel line to the carb. If it runs fine then it is the orings.

 

[1960-lonestar]

Re: 56 johnson sea horse problems

another thing to consider is the powerhead to exshuast tower gasket if its bad it will leak exshuast/water up into the engine compartment /and also choking out the carb? with exshuast and mostoir . 1960-lonestar

 

[56 rude]

Re: 56 johnson sea horse problems

for the water leak dont overlook the possibilty that one of the frost plugs is leaking(not sure if thats what you call them).you know those metal discs with the numbers stamped in them.just happened to a friend with the same motor.

 

[coolguy147]

Re: 56 johnson sea horse problems

spark plugs spark plugs spark plugs!!! they make ur motor go round and round

 

[wbeaton]

Re: 56 johnson sea horse problems

All of the above...

Also, did you check the coils? Even bad coils may give good spark and run in a barrel. Also clean and set the points.

Where did you set the jets after you rebuilt the carb? Intial settings are 1.5 turns out from gently seated on the low and 1 turn on the high.

You will have to remove the powerhead to replace the impeller, which you must do. Replace the mentioned base gasket at this time as well as the cork seal and o-ring that sits on thop of the driveshaft.

Find where the water is leaking under the cowl.

 

[zed2500]

Re: 56 johnson sea horse problems

Thanks guys for the advice. I won't be able to work on it until next week, but will let you know the results. Also does anyone know a good website to purchase parts for this motor. I have found several parts on ebay an a couple of other random websites, but would prefer to purchase parts from a knowledgeable source. Thanks so much for the pointers!!

 

[jbjennings]

Re: 56 johnson sea horse problems

laingsoutboards.com
The fellow there is very knowledgeable and helpful. Good, quick shipping. Make sure you ask if he has the part in stock, if he has to back order it, you may have to wait----and I hate waiting!
JBJ

 

[zed2500]

Re: 56 johnson sea horse problems

Well thank you all for the helpful information. Shortly after the last post, I pulled the powerhead to change the impeller. I went ahead and replaced the base gasket. After this, I fired it up. Unfortunately there was still water in the engine campartment. I was able to keep it running long enough to discover a leak from the bottom of the head. I pulled the head off to discover a blown head gasket. I have ordered a new one from Laings. I am currently awaiting its arrival, and hope to have it in a couple of days.

I will set up another post with the results of this repair.

thanks again,
Shawn

 

[wbeaton]

Re: 56 johnson sea horse problems

Are you sure it was the head gasket? There is also a welsh plug on the bottom of the head that frequently fails with age.

 

[zed2500]

Re: 56 johnson sea horse problems

I am pretty sure it is the head gasket. There is clearly a spot on the gasket where the seal has been compromised. The welsh plug appears to be ok. I guess I will find out soon enough. How easy are the welsh plugs to change, I have never done this before. Would it be similar to a replacing a freeze plug on a car motor??

Shawn