1986 Johnson 90, can I use top-engine cleaner on a 2-stroke?

[Danthehitman]

Hi everybody, I'm new to the forum and speed-boats, in general. My wife recently purchased an old Bayliner 1700 so I'm going through it a bit to make sure it's water-worthy. It's running a 1986 Johnson 90 that's VRO has been disabled (we're running pre-mix). We've had it out once, it did pretty well though it could use a little TLC.

I performed a compression check, yesterday, and have 85, 90, 91, 90 readings on the 4 cylinders. From what I understand, that's a bit low, 100 being the cut-off limit. I have had great experience bringing-up compression in Automotive applications using the AC Delco "Top Engine Cleaner", and am wondering if that's ok do do on a 2-stroke.

My process is to remove spark-plugs and pour about 1-2oz of cleaner in each cylinder, replace plugs, let sit 6 hours, remove plugs, then turn engine-over to pump out remaining fluid. This loosens-up rings that may be sticking from years of carbon deposits. I realize 2-strokes rely on oil to lubricate the cylinder so I want to ask any experienced folks their opinions.

Thank you in advance for your time!

Dan

 

[tpenfield]

Don't tell anybody but . . . I have used the Mercury PowerTune combustion chamber cleaner on my 2-stoke outboards

Seems to be fine. I have done both soaking the cylinder via the spark plug hole and actually squirting some into the carb while the engine is running at a fast idle. Does great in clearing out the mosquitoes from your yard too.

When I don't have a can of PowerTune handy, SeaFoam is a decent back-up . . . although PowerTune seems to work much better.

 

[flyingscott]

Yes Powertune or Yamaha ring free or BRP engine tune all work well. Get a different gauge because I doubt your motor would run with those compression #s

 

[Danthehitman]

Thanks for the replies, Ted & Scott! I think I'll try another compression tester before I go any further as you've recommended...this was purchased from the discount tool joint Harbor F____.

I'll keep you posted!

Thanks again,

Dan

 

[jimmbo]

I also Vote for Mercury's Power Tune and BRP Engine Tuner, never used the Yammiy Product, but it probably in the same League., You really don't have to try and drain the cleaner via the Spark plug holes, as two of the Cylinders will have had their Ports open and the stuff will have drained into the crankcase and Exhaust chamber, and the remaining two will do so too when cranked, unless you put enough in to Hydrolock the motor.

 

[Danthehitman]

Hey Jimmbo, thanks for the feedback. Yes, I was thinking if I perform a direct cylinder soak I'd have to do it in two separate procedures to avoid the open-port scenario.

 

[flyingscott]

Follow the directions on the can, they are there for a reason.

 

[jimmbo]

Real Men, never read Instructions, until after there is a Problem

 

[Danthehitman]

Real Men, never read Instructions, until after there is a Problem

I DEFINITELY don't need any problems with this outboard! haha...these guys are more expensive than I ever knew.

 

[Danthehitman]

Follow the directions on the can, they are there for a reason.

Do you know the basic procedure?...is it through the carb while running or is it directly into the cylinder? I'll get it on order and follow their procedure, just curious if this is similar to what I've done in the past. If it's through the carb I'll look forward to keeping that mosquito and bird population in check

 

[racerone]

Your motor will not run properly with those compression readings.-----Test again with a " known to be good " gauge !---Or remove the bypass cover ( side of the block 6 screws ) on the cylinder with 85 PSI.---A new gasket there will be cheaper than a bit of " mechanic in a can " in my opinion.

 

[Danthehitman]

Your motor will not run properly with those compression readings.-----Test again with a " known to be good " gauge !---Or remove the bypass cover ( side of the block 6 screws ) on the cylinder with 85 PSI.---A new gasket there will be cheaper than a bit of " mechanic in a can " in my opinion.

Racerone, thanks for that idea. I've got a service manual in route so I'll check that out, specifically.

 

[oldboat1]

Do the inspection and gasket, as described. But (ready for this?) if you want to clean out carbon build up, use a household spray bottle and mist water in front the the carbs with the motor running. Not much -- maybe two sprays, count to ten, then a couple more, and repeat. Expect to see some nasties blown out the exhaust just like with one of them store-bought products. It's as good as runin' in the rain.