1breakinit

you have a bad reed or 2 or 3.

stop running it before you kill it completely.

TopherMichael

Trying to understand why you think it is a bad reed(s)? Always helpful to understand what someone else is seeing wrong.

I hope the rebuild kits arrive today/tomorrow and I get a chance to clean the carbs and I think with the carbs pulled, I would be able to inspect the reed valves.

SweetD

Here's a great video explaining the reed valve's function and why it might be your problem. Worth a look if you're already taking the carbs down:

TopherMichael

Man, I watch his videos like it is prime time tv. Forgot about this video, thanks for posting.

Dacman

Wasn’t a great out come for him. But he is a good watch and informative.

If your carbs are not spitting out a fuel mist , I doubt your reeds are bad .

I think you could put a paper towel in front of each one held tight and see if one or more are pulsing. Meaning sucking air in and also blowing out an air mist when running.

A shade tree mechanics thoughts .

TopherMichael

Cleaned the carbs (really simple job) using isopropyl alcohol and a little carb cleaner. Replaced the bottom bowls, float, needle gasket, and side plate gaskets.

Did the pull the spark plug wire for each cylinder and I still have 1 cylinder (bottom right) that does not change rpms when you pull the spark plug wire. I believe there is fuel as the plug is wet, plug is gapped at 0.03.

I swapped the power pack top to bottom and still have the issue.

There is a spark and fuel as the plug is wet, just not firing.

I did place a shop towel in front of the intake and didn’t notice and blow back of fuel.

I am really stumped.

Dacman

That is weird , need a few things for fire, proper fuel air mix, compression and a strong spark.
One of them is not there. Or incorrect amount of .
Lots of fuel puddling in throats. Maybe flooding that cylinder?
Is the suction the same at all four carb throats?

TopherMichael

The puddling is from me covering the intake opening with a rag. Yes, appears to have good suction. I placed my hand in front of each intake and didn’t end up with gas on my hand.

Today I pulled the carbs again, this time I checked each needle valve. The top 2 needle valves were set to 9.5 turns and the bottom 2 were set to 7.5 turns.

I removed each needle valve, soaked them, and sprayed carb cleaner in each opening. Re-assembled and set all the needle valves to 6 turns. Started and let the boat run until the motor reached running temp. When I gave some throttle, the motor bogged down so I turned out the needle valves to 8 turns. That is when I captured the following video.

The motor no longer sneezes, however the motor still does not change RPM’s when I pull the same plug as before.

When I pulled the plug and put the plug back on, you could see the spark jump! Nice and dark blue.

TopherMichael

Wanted to quickly summarize the issue and steps to remedy the issue.

Since purchasing the boat last season, when returning to port, the motor would stall in no-wake zones. Just thought the idle was set low, never thought much of it. Then about 2 weeks ago, I was 7 miles offshore, had shut off the motor to do some fishing for about an hour. The motor did not want to start, took about 15mins for the motor to start back up again. We made it back, however, I noticed the motor ran rough hesitating and sneezing. When we were at the dock I removed the cowl and airbox to shoot some Johnson Evinrude OMC Engine Tuner down the air intake for each cylinder, which I am not sure did anything.

The next day, I attached the muffs and started the motor to troubleshoot. After the motor reached operating temperature, I pulled one plug at a time to figure out if I had a dead cylinder. Both the bottom port and starboard cylinders appeared to be dead. I then checked for spark via pulling the plug and attaching it to the motor, each had a good spark (I did not test with a gap tester). I then checked compression and each cylinder was around 90psi. I then swapped the coils and had the same outcome. I then swapped the plugs... same outcome. So I know I have spark and compression. Assuming I also have fuel as the plug was wet.

Per recommendations here, I pulled the carbs to rebuild and installed new bowls. Once again, I started the motor, it was still hesitating and sneezing, however, the port side lower cylinder was firing (3 out of 4).

I then pulled the carbs again, measured and removed each needle valve, and once again cleaned the needle valves and the throttle body plate. The top 2 needle valves were turned out 9.5 turns, which seemed like a lot. The bottom 2 were turned out 7.5 and 8.5 turns (kind of all over the place. I reassembled and set all the needle valves to 6 turns as I recall 6 is a good starting point. Motor ran like crap and would bog down when given gas. I turned out the top 2 needle valves to 8 turns and the bottom 2 to 7... much better as seen from the video in my last post. Still need to set these with the boat in the water.

With the motor running, I placed my hand in front of each carb, zero gas spit and each appeared to have a good vacuum. So I am thinking it is not a reed problem, however, I could pull and inspect this week.

At some point, this cylinder had to be firing this season as the plugs are new with the gap set to 0.03 and the plug clearly shows signs of combustion.

Besides that one time where the motor didn't want to start and the apparent rough idle/sneezing, the motor typically starts right up. Since I have been using the boat all season, the gas 89 octane with 360 stabilizer added, the gas should be good.

At the start of the season, I did the following tuneup
- new water/separator
- new Champion spark plugs gapped to 0.03
- new fuel filter
- new thermostats (didn't know the last time they were changed)
- lower end oil
- water pump
- greased all points and steering

So I am really lost what to look at now, if it was a carb issue, swapping the top/bottom carb should have resolved the issue. There is spark, compression and since the plug is wet, there should be fuel.

I have ordered a power pack and coil as I am really not sure why the motor is still running rough and sneezing. Perhaps the motor is fine and just needs some fine-tuning?

TopherMichael

Yesterday I replaced the starboard side reeds and played with the air mixture needle valves.

I was able to get rid of the sneezing, however after ~4 minutes of the motor running (using a bucket for a water source), the idle drops and the motor stalls.

I am now under the impression that the starboard lower cylinder is firing, as if I cover the intake for that cylinder, the motor will stall.

Since I am not really getting any traction with this thread, I am just going to take it to a local shop.

TopherMichael

Called around today and every shop is at least 3 weeks out (time to open myself a marina).

Is there anyone is the York/Kittery area that could help look at this motor?

Dacman

Did you try raising the idle with the detent idle timing tab? Or the base timing tab?
I noticed the idle is set fully one way but I can’t find which way raises in my book.
In your video. I saw it fully back.
Once the quick start releases on engine temp it may be falling too low?

TopherMichael

First THANK YOU for the suggestion!

I am going to pick up a timing light and go through the timing as I think you are on to something. Could the timing be off, causing that 1 cylinder to misfire?

I did order the DVA adapter to test the ignition system. So I am not waiting, I also ordered a new PP that includes the optical sensor and coils (just in case).

Also, the needle valves were set way beyond the 5 3/4 according to the book. Would like to drop the boat in the channel and set the needle valves.

Dacman

I think the base engine timing must be set with the adapter tool . Engine off.
When changing the optical sensor, clean and lube the slide points on the timing advance ring and make sure it is easily sliding back to the stop from the spring .
I’m just educated enough to make suggestions without much knowledge of what will get you fixed. Sorry.

TopherMichael

Thanks!

Just to avoid any further delays, I also ordered the stator. Can return if not needed, but with my luck, it will be needed.

SweetD

I'm in the same boat (ha pun intended) with pretty much the same motor, with a four week backlog at the shop I want to use! I'm above my pay grade at this point. Super frustrating as I know the shop could fix it in a couple of hours...just posted this today...

2005 Johnson 90 carb'd two-stroke #J90GLSOB - rough running at lower RPMs, video

Please keep updating your progress. I am also in the middle of a trailer hub rebuild and waiting on Internet parts for that...then I can pull the boat!

TopherMichael

If standing behind the motor, which cylinder is 1 - 4? I have the SELOC manual and cannot locate info on the cylinder layout.

Also, what is a TTL model?

orcaII

sweet d I feel your pain with this motor (I have the same year and hp) tho once going with a normal fuel pump and pre mixing a few years ago it’s been trouble free, my first move would be to verify the carbs are clean it’s a quick easy job, next would be to verify spark it almost seems like you are dropping cylinders due to weak spark, years ago I switched to a cdi power pack and optical sensor not saying that is your problem, I have a yammie 90 in the barn I keep threatening to throw on the boat which each minor issue I have had with this motor but so far I have been able to keep it going, I must say after a bunch of early bugs I was able to work out it’s been reliable but this era wasn’t a shining example of omc reliability for sure, I fish a bunch on a buddy’s boat with a 96 150 and that thing has been bulletproof and it’s basically the same engine minus two cylinders

TopherMichael

I did not try raising the idle yet. Perhaps I need to wait for the DVA adapter to arrive until I start adjusting the timing?

TopherMichael

It appears that someone replaced the PP in 2016 with the CDI PP. Do these PP not last long?