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Desperate for help finding 3.5 hp Johnson problem.

M

Mets Fan

New member
I have a 2 cycle 2004 Johnson 3.5 hp outboard model J3RSRE that I was doing some maintenance on. I have it in a pail full of water.

It won't start to save my life, not even with starting fluid.
I cleaned the carb clean as a whistle. Twice.

It's getting spark to the plug. Got a new plug anyway. gapped it and and double checked that I am getting getting spark. I used an inline tester as well as grounding the plug out of the hole.

Fuel filter is clear. Fuel is new and good. I found fresh fuel in the line and the carb bowl.
Compression checks out at about 130 lbs.
I did find a sheared flywheel key. I made a replacement while the original ships, but that didn't seem to be the issue. Probably sheered off from trying to start it so damn many times.
If I have any luck at all, its in the beginning, my first attempt of the day to start it. It will burb, and at best run for 2 or 3 seconds. After that, nothing, no burp, no smoke, nothing.

I just don't understand it, she just isn't catching. What do you think I can do from here?

 
Will the spark jump a 1/4" - 3/8" gap? Is the plug getting fuel? Try squirting some fuel into the plug hole. Are the reeds (leaf valves) just behind the carb opening and closing properly? You should be able to blow through the carb and it should make a noise like you are blowing through a saxaphone mouth piece.
 
Yes, the spark is jumping and there is fuel in there. I didn't blow through the carb but I shot some starter fluid directly in the carb throat, and another time I tried it directly in the spark plug hole. It's crossed my mind that it's flooding out because the plug is sometimes a little wet, and sometimes I see a drop of fuel near the choke plate. I'm not sure if all that is me trying to start it so much.. On the other hand I'm not able to see any fuel spritz up in the carb throat if I try to start it with choke off and throttle open. It's hard to see and start and the same time though.

It ran last time I went to the lake which was 2019. Nothing was touched or adjusted on it aside from basic storage procedures. The carb idle screw is two full rotations out from fully tight.
 
Does the spark jump a gap of 5/16" , yes or no ?-----Check that flywheel key again.----Sounds like it is sheared and your spark is at the wrong time.
 
racerone said:
Does the spark jump a gap of 5/16" , yes or no ?-----Check that flywheel key again.----Sounds like it is sheared and your spark is at the wrong time.
Click to expand...

I'll have to check a 5/16 gap. When the actual key comes ill put it in and give it another go. During one spark test, I didn't have the connection covered on one end and the spark arced quite far. Matter of fact it arched to the coil assembly. I dont think that would damage the ignition though, as it probably just went to ground. 8

Can a CDI ignition go bad and lose timing? Magnets on flywheel are strong and in place.
 
When I noticed your original post was at 1am I had a vision. You have been tinkering around, racking your brain, making parts and cleaning carbs all day and it's 1:00 in the morning. You have been pulling that rope "so many damn times" you have become "desperate". I feel your pain brother. I hope you have taken a breather and are feeling better by the time you read this. Your obviously mechanically inclined and a very smart guy. You will figure this out. I am guessing the inside of that crankcase was pretty juicy. Flywheel keys don't normally break no matter how many times you pull the rope, but it could break or shear if you pulled hard when there was a little bit of fluid in the cylinder.Im with racer one on this. Disconnect the fuel line and leave the plug out and wait for the new key. When you install the new key make sure you get that spark timing right. Don't even hook the fuel line up to it. There will be more than enough fuel left in the carb... I would pass on choke but open the throttle and start it.If it doesn't go on the first two pulls, try just a tiny puff of starting fluid. Good Luck. Peace
 
BoatDope said:
When I noticed your original post was at 1am I had a vision. You have been tinkering around, racking your brain, making parts and cleaning carbs all day and it's 1:00 in the morning. You have been pulling that rope "so many damn times" you have become "desperate". I feel your pain brother. I hope you have taken a breather and are feeling better by the time you read this. Your obviously mechanically inclined and a very smart guy. You will figure this out. I am guessing the inside of that crankcase was pretty juicy. Flywheel keys don't normally break no matter how many times you pull the rope, but it could break or shear if you pulled hard when there was a little bit of fluid in the cylinder.Im with racer one on this. Disconnect the fuel line and leave the plug out and wait for the new key. When you install the new key make sure you get that spark timing right. Don't even hook the fuel line up to it. There will be more than enough fuel left in the carb... I would pass on choke but open the throttle and start it.If it doesn't go on the first two pulls, try just a tiny puff of starting fluid. Good Luck. Peace
Click to expand...

Thanks friend. I've taken some time off working on it because I had done weddings and am still waiting on the flywheel key. Thanks for the encouraging words. Will definitely keep you posted
 
Mets Fan said:
I have a 2 cycle 2004 Johnson 3.5 hp outboard model J3RSRE that I was doing some maintenance on. I have it in a pail full of water.

It won't start to save my life, not even with starting fluid.
I cleaned the carb clean as a whistle. Twice.

It's getting spark to the plug. Got a new plug anyway. gapped it and and double checked that I am getting getting spark. I used an inline tester as well as grounding the plug out of the hole.

Fuel filter is clear. Fuel is new and good. I found fresh fuel in the line and the carb bowl.
Compression checks out at about 130 lbs.
I did find a sheared flywheel key. I made a replacement while the original ships, but that didn't seem to be the issue. Probably sheered off from trying to start it so damn many times.
If I have any luck at all, its in the beginning, my first attempt of the day to start it. It will burb, and at best run for 2 or 3 seconds. After that, nothing, no burp, no smoke, nothing.

I just don't understand it, she just isn't catching. What do you think I can do from here?
Click to expand...


As has been mentioned...have another close look at your ' key ' I've had this same problem with a couple of British Seagulls and it's easy to over look. Check closely inside the flywheel and also the main shaft, it only has to be scuffed and small amount to be way off. You will see a spark but the timing will be miles out. If it is the flywheel that's the problem, get another flywheel complete with key. If it's the shaft,...good luck.
 
Nobrot said:
As has been mentioned...have another close look at your ' key ' I've had this same problem with a couple of British Seagulls and it's easy to over look. Check closely inside the flywheel and also the main shaft, it only has to be scuffed and small amount to be way off. You will see a spark but the timing will be miles out. If it is the flywheel that's the problem, get another flywheel complete with key. If it's the shaft,...good luck.
Click to expand...

Thanks! Yep it was the flywheel key! Off just the tiniest bit, and the flywheel not torqued down enough. A good but tough learning experience. Never knew such a tiniest gap would throw the timing off that much.
 
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