83 johnson gt150 lake test #2 may have made serious mistake! UPDATE and TRIVIA

[motodave]

J150STLCTE Well I got all my fuel lines replaced, cleaned carbs again after sucking bad gas (already rebuilt them), and rebuilt the fuel pumps. Motor was idling better than it ever has, and the 'dead' spot at low rpms was reduced as well. Still a little rough idle but smooth once on plane. Seems like its 'loading up' like so many others with these motors complain. I wanted to make sure I didn't have a lean condition at high rpm so I got up wot, pulled the throttle to neutral and then turned the key off. Note: I now know this is not the correct procedure! Heres the plug readings port side

Starboard side


It gets even better. After doing this, I replaced the plugs with new ones, motor would not start. Every so often it would sputter and bang around but would not run. Someone told me they sheared off the flywheel key doing the WOT test like I did. Im panic filled to say the least. It was dark when I finally got off the lake, so I haven't checked to see if the flywheel did indeed slip. Visual inspection showed multiple spots like this in the photo. I knew the teeth were a little chewed up because the starter bendix would not engage every time, but I don't think it was this bad. Even worse I cant find a flywheel for sale even on ebay. Really worried a made a minor problem much worse! Any advice on how to proceed would be much appreciated! Taking to a shop not a good option for me

 

[racerone]

No need to panic at all.-----Remove the flywheel.---Inspect the key.---Note, replace with a factory key if sheared.----Clean up any damage on tapers using valve grinding compound.-----Install flywheel clean and dry.---Torque to the proper value.

 

[Faztbullet]

That the way tested em for years, and I myself never had one shear a key doing it....It would be the same thing if you was running down lake WOT and hit a wake causining kill tether to get pulled.

 

[gm280]

I guess I can't see the problem with the last picture. Is there some flywheel teeth broken off or something like that? I seriously don't see much wrong in that picture. Follow "racerone's" suggestions and see how that works...

 

[Bosunsmate]

Just move number one cylinder to top dead centre, is the timing mark on the flywheel lined up with the pointer on the engine- if so then your key is just fine

 

[motodave]

Hey thanks to all you guys for the responses, makes me feel better! gm20 its a bad picture but the teeth on the flywheel are getting rounded off, there are several sections like that, and the bendix doesn't engage when it hits those spots. I know I should have replaced the bendix as soon as I noticed it happening and I hope a new one will keep me from having to replace flywheel. Bosunmate that's the fist thing Im doing when I get off tonight. If I didn't shear the key, only other thing I can think of is maybe a plug wire broke or came loose, but Im always careful to pull/push from the boot. When I pulled the new plugs out, the port side looked dark already, and the starboard side looked like they never saw fire at all. Possibly a bad power pack? Thanks again guys

 

[Bosunsmate]

Id then double check you havent crossed some plug wires over to a wrong cylinder and if not then start checking spark... It could be a powerpack but could be a lot of other things too, after changing plugs and not starting id think wrong plugs or plug boot put on wrong cylinder (i do that now and again and it has the exact same symptom)

 

[motodave]

Thank you Bosunsmate I will sure check tonight to make sure I didn't cross any plug wires, after all I did it while floating across Texoma! The guy that towed me in last night said he had a motor like mine and switched to QL77JC4 plugs and had better luck, instead of the UL77V (flat top) that the motor calls for. Any experience with these?

 

[Bosunsmate]

Thank you Bosunsmate I will sure check tonight to make sure I didn't cross any plug wires, after all I did it while floating across Texoma! The guy that towed me in last night said he had a motor like mine and switched to QL77JC4 plugs and had better luck, instead of the UL77V (flat top) that the motor calls for. Any experience with these?

I dont know plugs that well sorry, but ive never had problems with flat ones. You have to be careful if you swap flat ones for ones with the electrode that sticks out because if they are at the wrong height ignition timing will be off and if too big they can hit the pistons

 

[motodave]

Thanks Brosunsmate, I appreciate all the help. Couldn't hurt to stick with original parts that's for sure. I have seen some motorcycle pistons get turned into a pile of pieces from people installing wrong plugs!

 

[motodave]

UPDATE and MYSTERY PIC - I found at least part of my problem, staring me right in the face and I cant believe I didn't catch it till last night. Its plain as day in the last photo, anybody see it? gm280 Im pulling for you on this one! BTW, cylinder #1 at TDC lines up with mark on flywheel, so as far as I can tell it did not shear the key.

 

[Mohawkmtrs]

...bendix hung up in the flywheel.

 

[motodave]

Winner winner chicken dinner! Still cant believe I didn't notice it, guess its cause Im a noob!Thanks to all for looking! Now Ive got to pull it off and lube it, have it tested. Will probably replace bendix and spring too

 

[daselbee]

I might have a flywheel. I can check today. PM me if interested.

 

[emdsapmgr]

Sounds like you are trying to do a high rpm "throttle chop" in order to "read" the plugs. Good concept, but hard to do with the center fire plugs. The just don't have a tip that shows much of anything. Works better with the J-tipped plugs. QL77JC4's. I know yours does not take them, nor do my older crossflow V6's. But for a single test run, I've swapped to them just for a short, single blast, then went back to the UL77V plugs after the test. Your plugs do look pretty sooty-good that you changed them. As you noted, best to have the engine in neutral when you chop, so that the prop rotation does not continue to turn the crank and bring more fuel into the combustion chambers-affecting your test results.

 

[daselbee]

No Title

Here is the flywheel I have....off a 1985 Evinrude 150. I am "sorta" sure this is a 10 amp flywheel...
Can someone verify this by looking? Parts list pictures show a vented flywheel for 1985, this is not vented.

I guess I should have said....parts lists show two flywheels for 1985. The ten amp and the thirty-five amp. The pic for the thirty-five amp shows vented.

 

[emdsapmgr]

Your engine is the GT/XP type 150. Model 150S. Came out as a high perf bass boat engine. Those all came with the upgraded charging system with the vented, 35 amp flywheel from the factory. The 10 amp (shown in your pic) was not made for your engine's charging system. It's used on the base 150.

 

[daselbee]

OK, so i have the base 150 10 amp flywheel, which is the same part number as the OPs 1983 150, which only had one flywheel option.
These are the same flywheels, OP...moto...

 

[motodave]

Thanks for digging that up daselbee, I know I have the 35amp system, shows flywheel part #0582403, so it is the same? Im ordering a new starter, think arco. Had mine tested and its bad, cost to rebuild is close to price of a new one with 1 year warranty.

 

[motodave]

And thanks for lookin out emdsap!