Did i just destroy my NEW (to me) motor?

[Average_azn]

Hi guys, I have a problem that I really need advice on. On friday I bought a used 12' Sears aluminum Gamefisher boat with a 6 HP JOHNSON OUTBOARD (only marking on the engine is 388904).
I took it out on the water today and the motor ran beautifully. Then, like the total noob boater I am, I tried to put it in neutral without turning the throttle to "SHIFT" position and ended up throwing it straight into reverse! It reversed for a few moments and then I panicked and shut it off.

Now here is the problem: It wouldnt start back up afterward! I tried for hours to get it start but no go.

I got it home, checked for fuel through the carb, it was good.
I checked the spark and was getting a good 1" spark on my tester (3KV according to my tester?)
Put in brand new plugs
Then I checked compression, Exactly 75 PSI on both cylinders. is that adequate compression?

I am at a total loss as for what to do next and I am utterly confused at how i caused this thing so much damage just by throwing it in reverse. Can anyone recommend next things to check? Any ideas on what broke when i slammed it in reverse?

Thanks in advance guys!

 

[bonz_d]

Compression, fuel, spark. Should run. That compression seems bout right for that small engine. How fast was it going when you killed it? There should be a safety stop inside that engine that prevents one from shifting it at high throttle. The number you give also seems to be a carburator from a 1978 6hp.

 

[Average_azn]

I was probably only a bit above idle. I think it should run too! I have blisters on my hands from pulling the starter. Thanks for the info, now i can start looking for parts if needed.

 

[Average_azn]

Do you think its a timing issue?

 

[nwcove]

maybe the " bang" from shifting at a high rpm sheared the flywheel key? ...just a thought.

 

[jakedaawg]

I think you flooded it. try again.

 

[Average_azn]

I came across that thought in my research as well, but the idea of removing the flywheel sends shivers down my back. If i put it in gear and gently pull the cord, the prop turns, would this disprove the sheared flywheel key theory? I dont actually know what the key does.

 

[Average_azn]

I just tried spraying starter fluid in the carb... nothing. took out the plugs and sprayed some in each. Still nothing. No sign of life.

 

[Phil K.]

The flywheel key keeps the flywheel and the crankshaft properly timed together. if the key is sheared or twisted it will change the timing of the engine. Most of the time causing the engine not to start. Another purpose of the key is to shear when the prop hits something so the crankshaft doesn't bend or the gear case dosen't get messed up. My guess is that when you put the engine into reverse it was as though you hit something (making the lower unit go in the opposite direction) and the key did it's job. If you take the nut off of the flywheel you may be able to see the slots in the flywheel and the crank where the key goes in. If they and not lined up perfectly replace the key.

 

[Robert Ellis]

The key basically sets the timing. As an expert at shearing keys lol, I can assure you that the prop turning by pulling the starter cord does NOT mean the key has not sheared. I was intimadated by pulling my first flywheel too ... but, it's not actually too bad a job.

 

[metriccrescentwrench]

I just tried spraying starter fluid in the carb... nothing

DON'T DO THAT!!!!!!!!! Starting fluid will wash oil off of internal parts and the piston walls.

You might be able to visually check the flywheel key without actually removing the flywheel. If you can't tell for sure then it shouldn't be a big deal to pull the flywheel.

 

[Average_azn]

DON'T DO THAT!!!!!!!!! Starting fluid will wash oil off of internal parts and the piston walls.

You might be able to visually check the flywheel key without actually removing the flywheel. If you can't tell for sure then it shouldn't be a big deal to pull the flywheel.

Oh GOD! Ill never do that again... The flywheel sounds like the culprit... does anyone have instructions or a link for howto take off or inspect the flywheel and key? I thought you need some sort of specilized tool thats probably no longer being made. Haha

 

[Average_azn]

The key basically sets the timing. As an expert at shearing keys lol, I can assure you that the prop turning by pulling the starter cord does NOT mean the key has not sheared. I was intimadated by pulling my first flywheel too ... but, it's not actually too bad a job.

What tools did you use? Do i have to order a harmonic balancer?

 

[Steve A W]

Average_azn
Here's a link to a post with a video about pulling flywheels.


Steve A W

 

[Average_azn]

Thanks steve, What do i do once i pull the flywheel? Where can i get another woodruff key?

 

[steelespike]

You have to get the key from a E/J dealer. It is specific to the motor.Be sure to torque the flywheel nut to 480-540 inch pounds.
Crank and flywheel bore clean and dry.

 

[Rick.]

For the record I'm voting on the flywheel key as well. Only because I can't imagine what else might be the problem and assuming (a dangerous thing when troubleshooting) the problem is connected with the accidental gear shifting. I don't get the potential for the key to shear as the driveshaft rotates in one direction regardless of gear shifting. I could see gear shifting causing internal gear case problems but not a flywheel key shear. Also, the poster mentioned the motor was slightly above idle. I do that shift on a regular basis with (up to now) no ill effects. Please make sure to let us know about the key. Best of luck. Rick.

 

[Robert Ellis]

Hi .... just watched the video ... pretty good really but a few problems with it in my opinion.

I could not believe that he had the plug wires attached!!! Never, ever do this - if you turn the flywheel, propeller. whatever and that motor starts you are in a world of hurt and for any future messages you'll have to type with your nose!

Also, I'm quite clumsy and **** happens so .... when I work on an outboard I always use a few rags to stuff those 'holes of doom' under the motor. Sure as anything, I'll drop something or something will fall out of my pocket etc and ... it's gone unless you want to take the lower unit off and go on a scavenger hunt. Marinas charge a small fortune for nuts, bolts and washers (eg - the big nut you remove from the crankshaft will be $20 please and thank you!)

Yes, you need an harmonic balancer (you may be able to borrow one but they are not all that expensive. Now, he mentions the bolts which is great but ... he didn't mention the corresponding plate washers - these need to be grade 8 as well.

Speaking of that nut ... he said on re-assembly that the torque was 40 ft/lbs. The implication being that that torque is correct for all motors. It's not ... be sure to check the correct torque for your motor. As an example, The motors I usually work on require 105 ft/lbs. You can probably borrow a torque wrench from the person you borrowed the balancer from lol.

He doesn't mention using penetrating oil - personally I give the joint a good soaking - preferably the day before I pull. As he mentions - all traces of it (or any other lubricant) must be removed before re-assembly.

Once you have the flywheel off - it's a great opportunity to install new points, condensers, check coils, plug wires etc. You'll be pleased to discover (apart from the coils) that stuff isn't too expensive and the spark you get afterwards will blow you away! You're in for so much fun lol.

 

[F_R]

I was probably only a bit above idle. I think it should run too! I have blisters on my hands from pulling the starter. Thanks for the info, now i can start looking for parts if needed.

Doing that at such a slow speed should NOT shear the flywheel key. I'm not saying yours isn't sheared, just that if is, shifting to reverse didn't cause it. What does cause it is somebody (in it's past life) had it off and did not reinstall it correctly. Flywheel and crankshaft tapers MUST be clean, undamaged, and dry. Then you MUST use a torque wrench to tighten the nut to 40-45 ft/lbs when reinstalling.

At any rate, the propeller drive pin should have sheared long before the flywheel key. You put no more stress on that motor than if you had hit a rock at wide open throttle. That doesn't shear properly installed flywheel keys either.

 

[Robert Ellis]

Hi .... just watched the video ... pretty good really but a few problems with it in my opinion.

I could not believe that he had the plug wires attached!!! Never, ever do this - if you turn the flywheel, propeller. whatever and that motor starts you are in a world of hurt and for any future messages you'll have to type with your nose!

Also, I'm quite clumsy and **** happens so .... when I work on an outboard I always use a few rags to stuff those 'holes of doom' under the motor. Sure as anything, I'll drop something or something will fall out of my pocket etc and ... it's gone unless you want to take the lower unit off and go on a scavenger hunt. Marinas charge a small fortune for nuts, bolts and washers (eg - the big nut you remove from the crankshaft will be $20 please and thank you!)

Yes, you need an harmonic balancer (you may be able to borrow one but they are not all that expensive. Now, he mentions the bolts which is great but ... he didn't mention the corresponding plate washers - these need to be grade 8 as well.

Speaking of that nut ... he said on re-assembly that the torque was 40 ft/lbs. The implication being that that torque is correct for all motors. It's not ... be sure to check the correct torque for your motor. As an example, The motors I usually work on require 105 ft/lbs. You can probably borrow a torque wrench from the person you borrowed the balancer from lol.

He doesn't mention using penetrating oil - personally I give the joint a good soaking - preferably the day before I pull. As he mentions - all traces of it (or any other lubricant) must be removed before re-assembly.

Prior to fitting the balancer, screw the big nut on a ways - that way, if the flywheel really 'pops' off (the sometimes do) - it wont go winging across the room - if you damage the flywheel ... time for a new motor.

I shouldn't say this too loud (many would disagree) but I'm not a fan of bashing anything on my motor with a hammer. I use a half inch drive impact gun (you know what garages commonly use to put wheels on and off) on the nut of the harmonic balancer. It's over in a split second and it's never failed me yet. Again, you can borrow one from the friend who lent you the balancer and the torque wrench (don't forget to borrow the appropriate impact socket too) lol

Once you have the flywheel off - it's a great opportunity to install new points, condensers, check coils, plug wires etc. You'll be pleased to discover (apart from the coils) that stuff isn't too expensive and the spark you get afterwards will blow you away! You're in for so much fun lol.