1975/70 HP Sea Johnson starts and then dies out

[Maj7860]

Hi All, A newbie when it comes to outborads.

I have acquired a 1975/70 HP Sea Johnson that starts but then dies before i can put this into gear. If I let it run for 20 or 30 seconds, it still dies out without even going into gear. Every now and then, it does go into gear and takes off. Could it be spark plug related, I looked at the spark plugs and two of them had stiky liquid outside the sockets where they go in. Also the spark plugs themselves were not dry when i took them out. The motor was running last year and was winterized according to the person from whom I bought it from.

Also, does anyone know what the gap supposed to be for the spark plugs. I have ordered the manual but have not yet received.

Any help will be appreciated.

 

[Solittle]

Re: 1975/70 HP Sea Johnson starts and then dies out

It could be spark plug related but you have a lot of things to do if you did not water test it or have it checked by a mechanic before you bought it. Like plugs, water pump, thermostat, gear oil and a tune up. Also check the FAQ section for one relating to awakening a sleeping outboard.

Oh and WELCOME!!!

 

[Jacob645]

Re: 1975/70 HP Sea Johnson starts and then dies out

Take a look at the timer base underneath the flywheel. Is it advancing before the throttle? If not, it will die almost every time. When it does go into gear, are you "flooring" it or accelerating gradually?

 

[Maj7860]

Re: 1975/70 HP Sea Johnson starts and then dies out

thanks for responding guys.

Jacob, when it does go into the gear, I am flooring it and then after a while I can gradually slow down and accelerate. I am going to look at what you suggested this weekend.

Thanks again for responding.

 

[wavrider]

Re: 1975/70 HP Sea Johnson starts and then dies out

Yes check the timer base to see if it is advancing fully when you advance the throttle.

It does sound lke a good carb rebuild would help, a link n sync also, spark plugs, and new impeller for the wqater pump.

If an engine sets up for any length of time it is highly lkely that the carbs will gum up with varnish requiring a rebuild. this guarantees the performance you are getting from your engine.

you have taken the first step in fixing your problems and the most important one, getting a manual.

Rebuild the carbs, re-plumb the fuel lines from the tank to the engine, rebuild the fuel pump, that way you have a complete new fuel delivery system, only thing left is carbs.

By doing the above you will have peice of mind in knowing your fuel system will not fail you out on the water.

the rest is just periodic maintenaqnce, tune up stuff, your manual will tell you how to accomplish this.

 

[Jacob645]

Re: 1975/70 HP Sea Johnson starts and then dies out

Totally agree with wavrider! Check the...no... Rebuild the carbs, don't just check them! Thoroughly clean the jets in them also. This and the pump will rule out a lot of things to start off with.
But, I had the same problem with my 1975 50 hp Evinrude. Take a look at your linkage and make sure that the timer base isn't being pushed up ONLY by the small bolt on the backside of the throttle cam. This is what was wrong with mine. The spring inside there that keeps the timer base advancing with the throttle was just not there! But I could get it to go because at about 75% throttle that bolt would begin to force the timer base forward. Therefore, by flooring it, the timer base advances quick enough that it isn't flooded before the spark advances. Take a look at this video. It was taken before I fixed it. Maybe it will help! http://youtube.com/watch?v=S9ryBVGlATo

 

[Maj7860]

Re: 1975/70 HP Sea Johnson starts and then dies out

Waverider and Jacob, thanks all of you for the great info, especially for the video (Thanks again Jacob), this really helps someone like me that has no clue about outboards and new to boating. I am going to try and look into all this over the weekend.


I actually had a boat shop look at my engine last week, he said he ran the motor and had found no issues (3 hrs of labor). He also had greased the lower unit and said everything else seemd to be good.

Anyway thanks for the info and I am going to see if I can do some of the troubleshooting myself.

Good thing, I have a back up 8 HP mercury.

 

[Maj7860]

Re: 1975/70 HP Sea Johnson starts and then dies out

Ok Guys, I have had an Evinrude/Johnson Specialist mechanic re-build my carbs, changed the fuel line and with the mufs on, the motor fired right up.

When i took it to the lake, it fired right up with choke and warm up lever up (idles at high speed). After ruuning a while, i stopped and tried to re-start, started in couple of tries with full choke and again warm up lever in high, brought it back at the doc and left it in neutral for a while where it dies after about a minute or so (warm up lever was low).

I tried to start it again to load onto the trailer and struggled to get it started, finally started enough to get me on the trailer and died before I could turn it off again. Once again, if it starts, it kind of dies when i engage the throttle. I have spent a total of $600.00 and still no peace of mind.

Any help would be appreciated.

 

[Jacob645]

Re: 1975/70 HP Sea Johnson starts and then dies out

Have you ever adjusted your idle mixture screws? Take a look at the FAQ section. This may solve your idle problem. It needs to be done on the water, so your mechanic may not have caught it, since all outboards idle fast on land.

 

[Maj7860]

Re: 1975/70 HP Sea Johnson starts and then dies out

Ok, I think my mechanic is trying to really steer me in the wrong direction here. When I mentioned the problem to him, he is saying that my exhaust port (two jets) should be above the water line. Is this true? I didn't check to see if they were submerged in the water or not when I took the boat out on the water. I always thought that these motors are designed such that even if the exhaust is in the water it shouldn't affect the performance of these motors. Isn't that what is called back pressure?

I am lost, I feel this guy is really found someone who is new to the boating (instead of a pleasure, its becoming more and more painful) and trying to take me to the cleaners.

Help????

 

[Jacob645]

Re: 1975/70 HP Sea Johnson starts and then dies out

Well yes, your exhaust ports should be above the waterline, but i think if the water was that much over the engine you would definitely notice it. Those ports are to release back pressure from the water when you're idling because of all the pressure on the exhaust at your prop. Do you have tilt and trim? If so, you could rule that out pretty quick, but in my opinion, it's probably spark advance or fuel related. Don't let it get to you! Figuring out what's wrong is half the fun! Did your mechanic perform a sync and link?

 

[Maj7860]

Re: 1975/70 HP Sea Johnson starts and then dies out

Thanks Jacob, appreciate the feed back. My mechanic moved the motor up by 1.5 inch and he has said that everything else is fine. New Carb kits, fuel lines and he did another compression check today and all the cylinders were at 145 PSI. He said that the motor is mechanically sound and there is not much he can do any more to it. He did ask me to remove my 8 HP mercury which I added on after i got the boat as it is ~ another 100 lbs added to the transom of the boat and he believes that is what is causing the exhaust ports to go under water.

I am going to run it with the mercury on as it has been raised by 1.5 inch.

He didn't mention Synch and Lynch, is this in addition to carb, or is this part of the carb re build.

Thanks for your continued help. Really appreciate it.

 

[Jacob645]

Re: 1975/70 HP Sea Johnson starts and then dies out

Sync and link is synchronizing your butterflies on the carbs opening as the timing is advanced. Each engine is unique, so you really should get a manual, which will show you step by step instructions for the process. Was your timer base advancing properly?

 

[Maj7860]

Re: 1975/70 HP Sea Johnson starts and then dies out

Jacob, sorry for responding late, was out of town. Anyway, it seems that cleaning the carbs has helped. Upon starting the boat, i no longer hve to floor it to get it going. It even idled ok for couple of times but still cuts off If i leave it in neutral for a while. Timer base is advnacing properly.

I think, I am going to check the fuel filter and see if it is cracked, it just seems that only reaosn it should cut off during neutral is that it is not getting gas.

Any thoughts?