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Outboard timing issue

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Psycon

New member
Hi all.
I have had some problems with my 8hp 2003 Johnson outboard. It ran ok to start with but then wouldn't go above half throttle. I checked the linkage which was all fine, changed the fuel pump, and rebuilt the carb. Took the boat out again and still the same problem. I decided to check if the timing was out by advancing it a tiny bit and this then got the engine running full throttle again so I'm pretty sure it's a timing issue. My question is, how do I set the timing myself? Is it something I should take to the proper mechanics to sort or can it be done myself?
Thanks everyone
 
I have discovered that my outboard has no manual timing adjustment. It says No maximum spark advance adjustment is neces-sary. Correct ignition primary lead position is all that is required to maintain proper ignition timing on 6/8 HP models. Orange/blue lead must con-nect to top ignition coil.
What is the correct ignition primary lead position?
 
flyingscott said:
Have you checked for spark? It sounds like you are running on 1 cylinder. And if it runs your wires are connected correctly.
Click to expand...

I haven't checked for sparks while it's running full throttle. What I dont get is if the timing is not adjustable, how come when i lengthen the rod that moves the ignition when you throttle up, the engine will rev fully?
 
The sky is blue so blue stripe on top.----Grass is green so green stripe on bottom.------Correct sounds like it might be running on 1 cylinder.-----Possible a broken wire from magneto to powerpack.-----Timing on these motors simply does not change from the factory setting.-----That is if folks just leave timing alone !!
 
You dont need to check for spark at full throttle only when it is idling. Does it rev up in gear when you move the rod or just in neutral? If it revs up in neutral it means absolutely nothing.
 
It idles fine and will drop revs when you disconnect each ht lead off each cylinder. It's when you accelerate on the water. It will rev up to about half throttle but stops accelerating on rpm. Now and again it tries to suddenly rev up for a split second. When I lengthened the rod by a couple of turns in the picture it nearly solved the problem. Not sure why though??
 
Perhaps there is an issue in the tiller handle / throttle cable.------Hard for me to diagnose this from 1016 miles away
 
I just realised all that it does by advancing the circled rod is the same as increasing the throttle a little. I am sure the throttle isnt sticking as when I'm running it without the cover on, the linkage is all moving correctly. From what your saying I think there could be a lose wire somewhere which is why its intermittent. Would the wire from the magneto to the power pack need me to remove the flywheel?
 
flyingscott said:
Does the carb open all the way? What happens if you pump the primer ball on the fuel line?
Click to expand...

Yes the carb opens fully and pumping the primer bulb makes no difference. It does seem like its electrical as when you have it full throttle and it's only running half rpm, it will twitch to try to run full throttle for a split second.
 
See post #5----Run with a timing light 1 cylinder at a time and observe the flashing light.-----Steady bright light then spark is good.-----No light occasional no light then you have found the problem cylinder.
 
Ok I am getting a timing light today so will test it. I am wondering if one of my ht leads could be shorting. There was a tiny hole on one of the caps that looked like it was bubbling a tiny bit after the engine was run. Didn't think anything about it at the time but could it be shorting from there? I have ordered a spark tester so will be able to see if the spark is jumping a half inch gap. I can see this is gona take a lot of fault finding.
 
Ok I tested the spark plugs with the timing light and both cylinders are firing fine and consistently. I did realise the spark plugs weren't the recommended ones so I put some fairly new ones in there that were the recommended ones to see if it makes any difference. I will take the timing light out on the boat when i go out next and if it does it still i will test again but reving and under load to check if both cylinders are firing at higher rpm. I cleaned up all the connections also and couldnt find any breaks. Fingers crossed it runs better this time!
 
Hey all. Just an update. I took the engine out today expecting it to still have issues but to my surprise it ran brilliant. Been on the water over 4 hours without a problem so seems to be sorted. Thanks for all the help :)
 
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