boat starts then dies

[brichbk]

Yesterday I took the boat out on the water and it started right away. I let it warm up for a few minutes then put it in reverse and it died. Started it up again, put it in reverse, it went just fine. Then I wanted to slow cruise around the lake and while underway it died. I couldn't get it started again. It would start up but then die as soon as I took my hand off the key. If you push the key in it acts as the choke. It did this over and over again. I noticed that it was blowing out a lot of blue smoke when it did start before it died again. I limped back to the dock with my trolling motor.

I went home to try to work on the problem. I thought maybe it was too rich in the fuel oil mixture. So I added about 0.5 gallons of gas to the tank and tried it again. It started without all the blue smoke and ran fine for several minutes. I shut it down and started it right up again. I did this several times. I even throttled it a little to see if it would die, it didn't. So I put 2 more gallons of gas and some oil in at a 50:1 ration and headed off to the lake to test it out.

I took it back to the lake to try it out again. The motor started, went in reverse and forward just fine. I ran slow, WOT, and in between and everything ran great. I found a place to fish, shut off the motor and fished for about 30min. I went to restart the engine, and it wouldn't start.

I'm not really sure where to start with the troubleshooting. I've searched and read different threads but couldn't quite find my duplicate problem. The carbs were just rebuilt, but not by me.

Johnson '77 70hp -- model #70EL77S

 

[73Trihull]

Re: boat starts then dies

I was going to say somethng about the carbs as well then you said you had them redone already. How does it do on the hose in the garage? Same issues or just in the water under load? Is the gas old? Check the fuel line and filter?

 

[brichbk]

Re: boat starts then dies

I just went out and looked at the fuel lines and when I squeezed the bulb I could see fuel going to the fuel filter. It was also the first time I've found that the bulb was soft and not hard, even after sitting for a few days it usually stays hard.

So I tried starting it and it started right up! I let it run for a few minutes then turned it off and pushed the warm up lever all the way down and it started again, with out choke. repeated it a few more times, started no problem.

I'm going to let it sit for a few and see what happens, when I try to restart it.

Can I pick up a fuel filter from an autoparts store or does it have to be a boat store?

edit: When I bought the boat a month ago it came with a full tank, I've used half a tank and added 2.5 gal to bring it back to almost full. So a mix of "before me" gas and new gas.

 

[CATransplant]

Re: boat starts then dies

This is an engine problem. Someone will move it to the Johnson/Evinrude forum.

 

[brichbk]

Re: boat starts then dies

so the motor is running fine on the hose. Starts right away. I put the top back on and the motor started and died. I took it off and it started. I left the motor running and put the top on and it died. I tried again, ran the motor, put the top on and I noticed a slight struggle to run. Could there be some kind of air intake that is blocked or clogged?

 

[Pokertrampp]

Re: boat starts then dies

so the motor is running fine on the hose. Starts right away. I put the top back on and the motor started and died. I took it off and it started. I left the motor running and put the top on and it died. I tried again, ran the motor, put the top on and I noticed a slight struggle to run. Could there be some kind of air intake that is blocked or clogged?

it sounds to me like you have an exhaust leak and the motor is not getting enought air with the cover on.

 

[brichbk]

Re: boat starts then dies

I'll check into the exhaust leak...

I talked with a local boat service center and they think it is a weak coil. The motor is trying to start with only 2 cylinders. What do you think? It sounds about right now that I think about it.

off to search the forums for "weak coil"...

Edit: This motor doesn't have a fuel filter only a metal screen, I checked it and it was clean. So I don't think it's a fuel problem.

 

[Pokertrampp]

Re: boat starts then dies

so the motor is running fine on the hose. Starts right away. I put the top back on and the motor started and died. I took it off and it started. I left the motor running and put the top on and it died. I tried again, ran the motor, put the top on and I noticed a slight struggle to run.

with this statement, i don't think it is a coil, if it was a coil it would do it with the cover on or off, the fact that it runs fine with it off tells me there is an issue with the motor not getting enough oxygen. classic symptom of an exhaust leak.

 

[brichbk]

Re: boat starts then dies

two questions:

1. How do I find an exhaust leak?

2. I had some grey gunk come out of the prop is it just dirt or something more sinister?

btw thanks for all the help so far.

 

[brichbk]

Re: boat starts then dies

so the last few days the motor has been starting and running fine with the hose in the driveway. So tonight I lowered into the lake and tried to start it, fired right up. I started it and stopped it several times, everything went fine. Tomorrow I plan on launching it and giving it a test run.

The only thing I've done is add some Seafoam to the gas tank. Well see what happens tomorrow.

 

[brichbk]

Re: boat starts then dies

took the boat in to the mechanic and he discovered that the gas tank cap was not venting (it's an old metal tank) and I need a new cap. He also found that the fuel line from the tank to the OB motor was not working. Both problems were intermittent but starving the engine of fuel.

The good news is that it wasn't too expensive and he tested the ignition system and found it in good shape and he tested the engine compression and all three cylinders were at 120. And changed the lower gear oil.

Now the boats ready for the water again....

 

[countvlad]

Re: boat starts then dies

took the boat in to the mechanic and he discovered that the gas tank cap was not venting (it's an old metal tank) and I need a new cap. He also found that the fuel line from the tank to the OB motor was not working. Both problems were intermittent but starving the engine of fuel.

The good news is that it wasn't too expensive and he tested the ignition system and found it in good shape and he tested the engine compression and all three cylinders were at 120. And changed the lower gear oil.

Now the boats ready for the water again....

good job on posting back the findings and on fixing the problem