35hp evinrude loses power in water

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axel2009

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I haved a 1979 35hp rude that seems to be running on 1 cylinder. 2 weeks ago I had the carb rebuilt and it seemed to run fine on the muffs. Once in the water it would only run on 1 cylinder, sputter a bit then the second cylinder would fire. It would run like this for a bit and then back to 1 cylinder. I changed the plugs and again at home on the muffs both cylinders fired without missing a beat. Once I got it in the water, same problem as before, only 1 cylinder would fire. When I pull the plugs the bottom plug looks great but the top plug is always wet with a oily looking substance. Any advice would be greatly appreciated.
 
jtexas

jtexas

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Re: 35hp evinrude loses power in water

ok, kinda depends on what "looks great" means to you, and what an "oily looking substance" is.

After idling, a light coating of oil on the plugs is normal. If it's wet with gasoline, sounds like the plug isn't firing. On the other hand, if "looks great" means it looks brand spanking new, like maybe it just came from a steam bath, that would indicate water getting into the cylinder. If it's bone dry, that means it's not getting fuel.

With the motor idling in the water, pull momentarily then replace the spark plug boots, one at a time. If the motor doesn't die, that cylinder is not making power. Remove the spark plug, reattach it to the boot, hold it against the engine block and look for a spark while somebody turns the engine over with the key. Use an insulated or plastic tool.

If it doesn't spark, swap the coils and test again. Problem follows the coil, replace it; otherwise, troubleshoot powerpack, timer base and stator.

If it does spark, then do a compression test:
http://forums.iboats.com/showthread.php?t=313963

If compression and spark are both ok, then that cylinder is not getting fuel -- I'd take another pass at the carb.
 
asdasc

asdasc

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Re: 35hp evinrude loses power in water

I just had this issue on my 18hp. Swapping coils is a lot of work, so first I got it running to make sure it would start easy. Shut it down, pull one plug wire, try to start it. If it starts, you know the other is working fine. Now put this one back on to test it and pull the other boot off. If it starts, you know they are both firing. If not, you know which one isn't.

Assuming only one is firing, try swapping the spark plugs and do it again. For me, the problem followed the plug, so it took just a couple minutes to replace the plugs and I was off to the races.

Of course, if that doesn't work, you are stuck with swapping the coils, then the condensors to see what is bad.
 
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axel2009

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Re: 35hp evinrude loses power in water

I will try the plug thing today. I am not engine savey so I dont know where the coils are. there are two black boxes where the plug wires come out of. Are those it? I thought I read somewhere that you have to pull the flywheel to get to the coils. I will post back in a few minutes after I test the plugs

Thanks for the replies
 
asdasc

asdasc

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Re: 35hp evinrude loses power in water

OK, I just looked up the magneto on shop.evinrude.com and found that you have one of them there e-lek-tron-ik ig-nishuns.

You are going to have to get advice from someone smarter than me if the plug thing doesn't fix it. I am sure the electronic ignition isn't that tough, I just have never played with one.

Good luck!
 
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axel2009

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Re: 35hp evinrude loses power in water

Update
I fired up the engine and pulled the bottom plug wire and the engine continued to run. I then pulled the top plug the the engine died. I then swapped the plugs and got the same results. Is there anything else I can check without getting to complicated for a novice? Knowing this, what do you think might be the problem?
 
asdasc

asdasc

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Re: 35hp evinrude loses power in water

My guess is that you have an ignition problem on the top cylinder! :)

I would think that you will need to pull the flywheel to do too much more. It isn't that hard if you have a gear puller. There is a great thread on doing it on older motors in the Top Secret File if you look there. There is a good exploded view of what is under there if you go to the shop.evinrude.com website. They also list all the part numbers and sell them there.

Good luck with it and let us know what you find.
 
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tx1961whaler

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Re: 35hp evinrude loses power in water

axel2009 said:
Update
I fired up the engine and pulled the bottom plug wire and the engine continued to run. I then pulled the top plug the the engine died. I then swapped the plugs and got the same results. Is there anything else I can check without getting to complicated for a novice? Knowing this, what do you think might be the problem?
Click to expand...
The problem is with the bottom cylinder. The top one is doing all of the work, which is why it dies when you pull the top cylinder plug wire.
Next step is to swap the coils around, and see if the problem follows the coil.
The coil is #42
convert
 
asdasc

asdasc

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Re: 35hp evinrude loses power in water

Oh gosh, you are right! Thanks for correcting me, the BOTTOM one has the issue.

Coffee is kicking in now, I should be fine. :)
 
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axel2009

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Re: 35hp evinrude loses power in water

I ordered new coils and should get them tomorrow. They dont look very complicated to replace so I will give it a shot. I will post back here once I know the results. Hopefully, this solves it. Thanks everyone for your help!
 
kenmyfam

kenmyfam

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Re: 35hp evinrude loses power in water

Good Luck and let us all know.
 
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axel2009

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Re: 35hp evinrude loses power in water

Here is an update... I put my new coils in today and I have the same problem. I used a spark tester and still no spark on number 2. I swapped the coils and again no spark on number 2. What is next in my future. Is it possible for the power pack to go bad and still fire 1 coil? I am on a mission to get this damn thing running :). Thanks for looking!!!
 
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tx1961whaler

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Re: 35hp evinrude loses power in water

Yes, it is possible for the power pack to go bad on only one side. That is why it was suggested to swap the original coils around to see if the problem followed the coil around or stayed with the power pack signal.
 
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axel2009

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Re: 35hp evinrude loses power in water

With whats going on in my case do you suspect the power pack? Or is this a case of "could be many things" Im not sure how eveything works so I wouldnt know where to look beyone the power pack
 
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axel2009

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Re: 35hp evinrude loses power in water

Final update:)
I replaced the power pack and she now runs like a top! Thanks everyone for your help. This DIY stuff is kinda fun!!
 
asdasc

asdasc

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Re: 35hp evinrude loses power in water

Yes, it is rewarding, isn't it?
 
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