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2000 70hp Johnson electrical problem?

RandellWNY

New member
I have a 2000 70hp Johnson that I recently purchased used so I know little about it's back ground. I will outline what happened below and maybe someone has an idea of whats wrong.

Drove the boat about 4 miles out in Lake erie fishing with boat running great.
Made 5 drifts over a spot about 1/4 mile long.
Down time durring drifts about 20 minutes.
On the 6th run back up to my starting point the motor started to spit and sputter and finally was nocked down to only running at an idle.
If you attempted to go any faster then idle the motor would shake spit sputter and look like it was going to come off the engine mounts.
Changed the spark plugs with no help
I was able to get a little (very little) more rpm out of the motor for a while with the cover off. but it seemed to heat up and go right back to idle only
Motor did not seem "hot" and no horns sounded.
Idled all the way back in and each time I tried to go ove idle it would spit and sputter badly
Took it to a marine shop and they started it about 40 minutes after it was out of the water and not running. It started right up and ran great for about 45 seconds and then started to spit and sputter.
They could not get to it for a week and when they did they found nothing worng. they said they ran it for 45 minutes and could not recreate the issue.
I took it down to the launch and ran it myself for twenty minutes and it never has run better

Sorry for the book above but I am at a loss and the marine place does not know what to do with it and I have no trust in it. Any help would be great

Thanks
 
How old was the fuel? If you finally worked your way through a bad batch of fuel it could explain what happened. I had this sort of thing happen early last season and it ultimately resolved itself.
 
fuel was fresh and it was real gas vs. gas/ethonal. It is also the same fuel that is in it now and it runs like a champ. I hope I never see it happen again but I honestly have no faith in it at this point. I fish the niagara river and on one end is the peace bridge and the other is the Niagara Falls. Hard to navigate either one.....LOL I honestly wish it would break again so I could actually fix it.

I also pumped the ball on the way in and it had no efect so I don't think it was fuel pump. when it started to spit and sputter I also tried chocking the motor and it had no efect either other then sthalling it out eventually. It restarted but you could not rpm up even in nuetural.
 
fuel was fresh and it was real gas vs. gas/ethonal. It is also the same fuel that is in it now and it runs like a champ.

My thinking is there could have been some water in the fuel. My boat's fuel pickup is at the bottom of the tank, which is where water will settle out of fuel. After you get the water sucked out of it, it will run pretty well on the fuel that was riding on top! :D

I understand your concern about trusting the motor. I wouldn't be out on the lake (Lake St. Clair, a whoppin' big one!) without a membership in BoatUS. For $75 a year you get what's like the AAA of the water, unlimited towing. You can call for help via VHF radio or cell phone. If you don't have this, it's really worth the peace of mind. Once you know you're covered for all the possibilities, you can enjoy your boat even if it's not 100% reliable if you're careful about staying out of bad weather.

Good luck!
 
I see that both the responses are targeting fuel and who knows maybe it was the fuel. My question then would be how could I have made it in 4 miles on a motor running at idle as smooth as a kitten. It did not as much as hicup all the way back in as long as you did not go over an idle. Either way that was a great tip for the boat USA towing. 75.00 is nothing when your out that far
 
Seems like not running the motor under a big load will mask a lot of problems with fuel and spark. When you call on it to really create some power, those sorts of issues will rear their ugly heads. Hope you don't need that towing insurance, but better off having it! :D
 
you sure it didn't go into slow mode? have you checked the alarms on the motor/boat to make sure they are working?
 
I checked for alrams and or lites and neither went off.

Today i took it out on the water and it did it again but this time I think for good. I have no spark at either cyl and then all at once the motor wil spit if you keep trying to crank it. When you pull the spark plug wire no spark or it must be very intermitment. At least now it's broke and hopefully we can track it down
 
Just a follow up... The marine shop found the problem to be the power pack. Hope this helps anyone else looking into similar problems.

thanks for everyones suggestions and help
 
One thing that puzzles me.Did noone tell you to check your ground connections?I had the identical problem last week.My motor idled great,but at any amount of throttle it would sputter.A marine mechanic told me to change just about everything.Giving the motor one more chance at life,i cleaned my ground connections,and presto,it runs like new.
 
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