# Johnson 3 cyl 35 hp - Runs for while then dies



## rktman (Apr 25, 2016)

I inquired in another post about a possible fuel pump issue but I'm starting to think my 3 cyl Johnson 35 hp is having electrical issues.

I took it out last weekend and it ran fine for a 20-30 minute run.
I stopped for a while to fish and then tried to take off.
It sputtered and died like it was fuel issue.
I pumped the fuel bulb and it started and ran for 30 sec and died again. 
It repeated this for 5-6 times. 
I took the case off and checked for fuel in the filter, loose connections, etc.
I started it and it ran long enough to get me to camp.
The next morning it started and ran fine for 20 minutes back to the boat dock.

So, this weekend I did the same thing. 
Ran for 15 minutes up river, stopped to fish, ran 10 minutes down and it sputtered and died as before.
Then it was the repeated Start, run for 30 sec, die.

Sorry for the long post but does this sound like a powerpack issue?


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## perchjerker (Apr 25, 2016)

are you getting spark when this happens?


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## rktman (Apr 25, 2016)

Honestly, I've been afraid to shock myself to check but I will get an inline spark tester and check it this weekend.


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## perchjerker (Apr 25, 2016)

all you have to do is when it happens take a plug out of the motor and ground it to a bare metal engine part and crank it and see if there is spark or not

you could make a simple jumper wire with alligator clips on each end and ground it that way so you are not holding it

but a spark tester is fine too


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## hildebrandr990 (Apr 25, 2016)

Make sure that the breather on fuel tank is working run it till it shuts off open the cap and pump the bulb leave the cap loose and see if it runs

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## billyjoebigdaddy (Apr 25, 2016)

I had a similar issue with my 9.9 merc. I had a 6 gallon fuel tank with a vent in the cap. I just dealt with it for a while. Then for a completely different reason I switched the tank. I wanted a smaller tank to save room and weight. I got an Attwoods 3 gallon ventless tank. I have not had an issue since.


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## Pappy (Apr 26, 2016)

"Sputtered and died" is not a good enough description to go on. 
What RPM were you normally running at when this happened? On plane? Idle?
Did the engine shut down as if you turned off the key so to speak? 
Hint here is that a fuel issue will be less abrupt than ignition issues. 
If you try and start the engine immediately after one of these shut downs what happens? 
If it will not do anything no matter what you try then later starts if nothing ever happened that would be good information as well. 
Fill in the gaps here and we can start on it. 
I would not remove a plug and hold it against the block by the way. Plug wires are short enough that the spark may catch the fuel blowing out of the cylinder and light it off. Inline spark checker is the easiest followed by mechanical spark checker.


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## rktman (Apr 26, 2016)

Pappy said:


> "Sputtered and died" is not a good enough description to go on.
> What RPM were you normally running at when this happened? On plane? Idle?
> Did the engine shut down as if you turned off the key so to speak?
> Hint here is that a fuel issue will be less abrupt than ignition issues.
> ...



Thanks for replying Pappy,

Full RPMs and on plane when it cuts out (after the first 15-20 min of running)
It does not quite shut off all the way. It will idle a few seconds and then finally die out like its being starved for fuel (primer bulb pumping does not help, vent is open, fuel system seems unrestricted). Water is coming out the pee hole at the normal rate.
After a little while (30sec -1 min), it does start back up and will even get to full RPMs and back on plane for 10-15 secs (thankfully it will get me over a thin shoal before it cuts out again). The longer it sets the longer I can run (especially with case off). 
I went by the parts store and purchased an inline tester, will try it out as soon as possible.
A buddy mentioned that it might be the thermal sensor throwing it into slow mode, not sure how to check that without replacing.

It is a jet and not real easy to try the hairdryer trick.


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## hildebrandr990 (Apr 26, 2016)

Seen this too many times to remember loosen the cap on the tank bet it will run all day I have even seen fuel tanks cause this with the carbs full of gas and the more gas that is in the tank the less time it will run before it shuts off

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## billyjoebigdaddy (Apr 26, 2016)

I agree with hildebrandr990. That was the same thing that happened to mine. I think it was getting vapor locked. When I switched the tanks out it stopped.


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## Pappy (Apr 27, 2016)

There is a simple check to verify what is mentioned above is happening. 
The primer bulb will be sucked flat while the issue is occuring. If the tank cannot supply fuel for whatever reason the resultant fuel pump vaccum will flatten the bulb. 
Easy check.....take another tank with you.
There are two fuel pumps on that engine but you can always squeeze the bulb (as long as it is not flat) to verify a fuel supply issue to the engine.


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## rktman (Apr 27, 2016)

Pappy said:


> There is a simple check to verify what is mentioned above is happening.
> The primer bulb will be sucked flat while the issue is occuring. If the tank cannot supply fuel for whatever reason the resultant fuel pump vaccum will flatten the bulb.
> Easy check.....take another tank with you.
> There are two fuel pumps on that engine but you can always squeeze the bulb (as long as it is not flat) to verify a fuel supply issue to the engine.



No suck flat going on, but I do have a spare tank and newer bulb. I will take it with me on the next outing.


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## rktman (May 6, 2016)

Ok, it is not a fuel issue
It is a hot fail spark issue.
I tried the tank swap, took lid off tanks etc, primer bulb is good and has pressure.
It will run fine with the motor cover off.
If I run it for 15 min and let it set with cover on, the heat accumulates and causes a failure somewhere, I assume the power pack is the most common failure point?


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## Pappy (May 6, 2016)

If you replace a pack replace the sensor with it. (The electric eye)


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## JaguarJim (May 8, 2016)

rktman said:


> Ok, it is not a fuel issue
> It is a hot fail spark issue.
> I tried the tank swap, took lid off tanks etc, primer bulb is good and has pressure.
> It will run fine with the motor cover off.
> If I run it for 15 min and let it set with cover on, the heat accumulates and causes a failure somewhere, I assume the power pack is the most common failure point?


Hey bud have been having same kind of issues with my 3cyl 25 Johnson, you can usually tell if the switch box is acting up on these motors because either the quickstart doesn't activate on startup or never shuts off leaving it on high idle, unfortunately there is no way to test these packs, and new OEM one will set you back almost 500, optical timer base isn't cheap either. I've changed carb parts, rebuilt fuel pumps, even changed all fuel lines through out, and reset idle needles on mine, helped a little, but still wanting to die after restart and running down the lake. If you have service manual, go through it, and look at the idle sync section make sure all that stuff is set correctly, mine wasn't and mine was installed by an OMC/BRP dealer who should've known better, that was bought to my attention by some other members on here, that I needed to check that stuff before proceeding, it helped a bit, but I too am in suspect of the switchbox now. On these motors they are notorious for going bad, the newer version of box after 1999 is supposed to be better, but have heard of guys burning newer ones up too.


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## rktman (May 10, 2016)

Jaguar Jim,
What did you mean by the quick start?
I've noticed it takes a few times trying to start it (2-3) before it fires up (even after running for a while).
Before it would start right up.
Thanks.


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## perchjerker (May 10, 2016)

rktman said:


> Jaguar Jim,
> What did you mean by the quick start?
> I've noticed it takes a few times trying to start it (2-3) before it fires up (even after running for a while).
> Before it would start right up.
> Thanks.



I found this for you doing a search from a post on Iboats

QuikStart is a feature of the powerpack that advances the timing whenever the engine is started. After five seconds, the timing will return to normal if the engine temperature exceeds 96 degrees or if the RPM exceeds 1100, whichever occurs first. The change in timing is quite noticable. 

Most of the QuikStart powerpacks have a black and white wire from the temperature switch on the cylinder head in addition to the normal tan wire for the alarm.


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## rktman (Aug 1, 2016)

I know this is old but I still haven't tracked the problem down yet. Purely by coincidence, I watched a guy running his Evinrude 3 cyl 25 hp (same motor as my Johnson 3 cyl). 
His did the exact same thing. It will run fine for a 5-10 minutes, then starts coughing, then just dies. Wait a few minutes, runs fine (only for a brief period), shuts down..repeat.
Pumping with a hard bulb doesn't change anything, fuel is in carbs and filter. Like me, the other guy replaced plugs, CDI box at $400, switch primer bulbs/tanks, cleaned carbs, checked compression, stator checked, unplugged temp sensor, etc. 

It seems to be a hot fail condition somewhere but its hard to diagnose.

Any recommendations? Its just too good of a motor to give up on.


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## Florida_Native (Aug 1, 2016)

Maybe this sounds obvious but how old is the fuel? The fuel we get now from gas pumps contains ethanol, which if left in a tank for 3 weeks or more it will start to turn to water. 

I know it sounds strange but has happened to me numerous times. I only use non-ethanol fuel now, it's harder to find and more expensive but it runs much better in a boat. 


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## rktman (Aug 1, 2016)

Florida_Native said:


> Maybe this sounds obvious but how old is the fuel? The fuel we get now from gas pumps contains ethanol, which if left in a tank for 3 weeks or more it will start to turn to water.
> 
> I know it sounds strange but has happened to me numerous times. I only use non-ethanol fuel now, it's harder to find and more expensive but it runs much better in a boat.
> 
> ...



Different tank, all new gas and oil mix, same result.


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## Florida_Native (Aug 1, 2016)

Not sure then, I have almost the same motor. A 97 evinrude 25hp however mine is a 2 cylinder. Thing runs like a champ. 

When it dies, is the primer bulb still hard? 


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## Pappy (Aug 1, 2016)

Sounds like you replaced the power pack only. 
If you scroll back up to page one I told you to replace both the pack and the eye. They should be replaced together. 
Florida Native....your engine isn't even close to these 3-cylinder engines!


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## Florida_Native (Aug 1, 2016)

Pappy said:


> Sounds like you replaced the power pack only.
> If you scroll back up to page one I told you to replace both the pack and the eye. They should be replaced together.
> Florida Native....your engine isn't even close to these 3-cylinder engines!



Yeah a lot better I guess! 


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## rktman (Aug 2, 2016)

It seems odd the electric eye would be affected by heat, since its not a coil type device but I'll try anything at this point.


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## perchjerker (Aug 2, 2016)

rktman said:


> It seems odd the electric eye would be affected by heat, since its not a coil type device but I'll try anything at this point.



any electronic component can be affected by heat


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## Pappy (Aug 2, 2016)

rktman said:


> It seems odd the electric eye would be affected by heat, since its not a coil type device but I'll try anything at this point.



Rktman - I know you may not trust what I am telling you. May ease your mind to read profiles of those who are trying to guide you once in a while, no matter the forum you are in.


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## rktman (Aug 2, 2016)

No offense intended pap, just have to spend money carefully on a 17 year old motor.
I really dislike the replace it and see what happens method but apparently there is no way to test the Electric eye sensor.


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## perchjerker (Aug 2, 2016)

rktman said:


> No offense intended pap, just have to spend money carefully on a 17 year old motor.
> I really dislike the replace it and see what happens method but apparently there is no way to test the Electric eye sensor.



If you take Pappy's advice you ARE spending your money carefully


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## Pappy (Aug 2, 2016)

Wasn't offended in the least. You will get a lot of recommendations here that are either solid or can cost you one Hell of a lot of money. By reading the profiles sometimes you gain insight into who may have a better chance of helping. 
Hey, sometimes I don't take my own advice! 
I own (4) of the 3-clyinder Looper 25/35 engines and had your same issue this spring. The engine I am talking about was a 1996 or 20 years old. Doesn't owe me a dime at this point. 
I popped a pack on it and Lesa and I made it about 15 miles and poof. Luckily we were sort of on our way back. The trolling motor took us a full 9 miles back to the ramp. Did what I knew I should have done to begin with and put the eye on there and was good to go. Not to say there is a guarantee to anything I ever recommend doing but the best dealers out there were replacing both as a pair on the 60 degree V-4 and V-6 engines to keep comebacks to a minimum. It's not like we knew everything, dealers taught us as well as engineering did and whatever advice I give is based on one Hell of a lot of experience. Nothing more nothing less.


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## rktman (Aug 14, 2016)

I replaced the timing base/electric eye and ran it for 2-3 hours with no problems. Thanks for the advice Pappy.


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## Pappy (Aug 15, 2016)

Great! Thanks for letting us know.


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## rbdingwe (Sep 26, 2021)

Pappy said:


> If you replace a pack replace the sensor with it. (The electric eye)


I have just started having the exact same problem with my 1997 Johnson 35hp. I had replaced the power pack 3 years ago but this is the first time I ran into the complete shut-down problem while running at full throttle for 5 to 10 minutes. When you say "replace the sensor", what part are you referring to. Is this sensor located next to the spark plugs? I found a picture in a manual for 35hp Johnson motors but I can't seem to paste it in these notes.


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## rktman (Sep 27, 2021)

Its the pickup sensor under the flywheel (replace at the same time as powerpack). I think its OMC part # 0584824, but I would double check on boats.net or similar for your model number.

(Sent via PM also)


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## RaisedByWolves (Sep 29, 2021)

rktman said:


> Honestly, I've been afraid to shock myself to check but I will get an inline spark tester and check it this weekend.



Just take the shock.

I used to collect Homelite chainsaws and the easy test to check for a bad capacitor if you had spark issues was to hold the plug wire while pulling the motor over.

If you felt one zap the capacitor was good, if you felt three distinct zaps the cap was not doing its job.

I’m mum mum mosstly oak oak OK after du ddoing thi thi this fu fu for ye ye years. :x


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## RaisedByWolves (Sep 29, 2021)

rktman said:


> Pappy said:
> 
> 
> > "Sputtered and died" is not a good enough description to go on.
> ...


Here’s what a motor in limp mode due to a bad temp sensor acts like, overheat condition should be the same.


https://m.youtube.com/watch?v=UwMU9Q5_XP0&feature=youtu.be


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## rktman (Oct 4, 2021)

RaisedByWolves said:


> rktman said:
> 
> 
> > Honestly, I've been afraid to shock myself to check but I will get an inline spark tester and check it this weekend.
> ...


Its been 5 years since that post but yeah mine is fixed, lol. 
The reason this thread is active is because someone else was having a similar problem.


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## rktman (Oct 4, 2021)

RaisedByWolves said:


> rktman said:
> 
> 
> > Pappy said:
> ...


That's not what the 3 cyl acts like when the sensor eye is going bad.


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