1986 Johnson 175 missing

[wayno01]

I just completed a complete rebuild and everything is new. Pistons, rings, bearings, everything was replaced internally. All electronics were replaced with CDI components. Timer base, stator, power packs, I have strong spark and 115 lbs of compression on all cylinders but I have a miss. It almost sounds to me like a cylinder is firing out of order occasionally. When I pull the #2 spark plug it is black with soot. If I clean it within a minute of running it is black again. The carbs were also throughly cleans and I changer the high speed jets 2 over factory. Any ideas what is going on?

 

[ct1762@gmail.com]

what do the other plugs look like? sounds like it's running rich 2 over. did you check the parts manual to make sure the orifices weren't oversized/replaced to begin with?
if it's missing, i'd also make sure those carbs are really clean and the float drop settings are correct. i'd also check the DVA voltage at the primary wires to make sure they are getting 150v+ at idle. swap the coil and see if the fowling follows that cylinder.

 

[ct1762@gmail.com]

you can hook an inductive timing light to #2 to make sure all cyl are firing at the correct time

 

[wayno01]

All other plugs look fine. The carb shares a cylinder and the other cylinder is fine. I have checked with a timing light and didn’t see an issue. I’m going to replace the plugs tomorrow and check with a timing light again. I had weak spark in the #1 cylinder and replaced the power pack on that side since it was the only thing I haven replaced. The #2 cylinder has a new coil on it. When I pull that plug is dry and black with soot.

 

[racerone]

Each carburetor bore feeds just 1 cylinder.-------Take the top carburetor apart.----Maybe the high speed jet in the bowl is missing.

 

[wayno01]

I’m sure the high apps jet is in. I will pull it apart to verify everything is intact and clean. The only other thing I can think of that would cause this is an air leak somewhere.

 

[racerone]

I doubt it is an air leak.-----But good luck with it.

 

[Faztbullet]

#2 coil cold have a problem, also index flywheel and check timing as flywheel magnets where a problem these year models. Something is causing the CDI junktronics fire the cylinder late and it could be the CDI replacement parts

 

[wayno01]

Thanks for the suggestions. I agree on the possible CDI electronics issue. I hear a pop out of the exhaust occasionally. I believe I have several issues one being the carb. I checked the magnets when the flywheel was off but I may pull it and put the original timer base back on and will check it again. I also want to check the spark on cylinder #2. I can clean that plug and fire it up for a minute and it’s black and dry when I pull it. I’m afraid of damaging that cylinder.

 

[wayno01]

Thanks Faztbullet, you were right on. My flywheel magnets are loose. Three of them slid together and the other three came out with very little pressure. I can tell where they were glued in but not sure of the orientation. Three pull opposite of the others. Also what should I use to reattach these?

 

[racerone]

Factory ( BRP ) has an epoxy kit just for that job.-----Other epoxy materials may also work.

 

[wayno01]

I’ve been looking for information on the placement of the magnets and can’t find anything. Three are different from the other three as far as the direction of magnetic pull. Does anyone know if it matters where they are installed?

 

[ct1762@gmail.com]

the actual orientation doesn't matter, just as long as they are evenly spaced with a 7/16'' bolt. makes them perfect. also check the timer base magnet ring in the center to be sure it didn't shift. i've used the grey jb weld on these with no issues as well.

 

[DRCrowe]

Make sure you clean the surfaces before reglueing. I had a similar issue. I still had a few magnets intact and indexed them with a sharpie which assured the others were in the correct location when I glued them all back. I actually used sharpie markers to space the magents. It was a tight fit and really pressed the magnets into the flywheel while the glue set. I have also heard people use fuel line as spacers. Good luck!

 

[wayno01]

Thanks for all the help. It’s all cleaned up and just waiting for the epoxy I ordered to come in.
this rebuild has been one thing after another getting this back on the water. They shipped me the wrong pistons, found minor damage to the crank when I went to reassemble decided to replace it. A few connecting rod bolt stretched replaced them all, stripped a head bolt in the block, fuel pump leaking, replaced it and now this. Thanks for all the help on this project. All this because I purchased the Grady White I always wanted. Unfortunately the alarm was disconnected when I purchased it so I had no idea there was a problem. I have to wonder if the previous owner disconnected it knowing there was a problem.

 

[ct1762@gmail.com]

hey never tried the sharpie trick! yet another example for your viewing pleasure:

 

[wayno01]

I reattached the magnets and I still have a problem. I am getting a backfire out of the exhaust. I’m thinking the trigger magnet moved a little and is causing the problem. I will attach some pics if anyone can give their advice. If this is the problem can it be fixed or do I replace the flywheel?

 

[ct1762@gmail.com]

i would grab a new used one . i guess someone could chime in here and say its possible to take it off, clean and re-epoxy, but it needs to be in the exact right position for the sensor assembly to trip the powerpack switches at precisely the right moment. maybe OMC made a special tool at one point to re-set these.

 

[Faztbullet]

Wrong diagram as that's for looper..you have a crossflow

 

[wayno01]

This is the only diagram I could find.
would the 1988 - 92 crossflow be the same? I tried to move the magnet I wrapped it in leather and used a big pair of vice grips and it doesn’t move. I find it hard to believe it moved on its own. I have been searching the internet for a picture of my flywheel that shows the magnet but haven’t found anything that can be seen clearly to rule this out as the issue. It’s definitely firing out of time but not consistently. It fired up and sounded better but has an occasional pop through the exhaust and I am unable to bring the idle down without it stalling. If the magnet were the problem I would think it would be constant and constant. It’s either the magnet moved or the new CDI timer base is junk.