1989 Johnson 88 running rich at idle

[RoGun_Mako171]

Thanks for the input matersammich. Before cleaning up the power pack leads and ground did you do a spark test and it looked ok? My spark test looks good, although having a good "snap" is subjective and I don't have much experience with these engines and could be wrong. What tests in the service manual lead you to the power pack as the problem?

 

[matersammich]

I had spark ( and a poor Idle) before I started with the link and sync. After none. I may have bumped something or the gremlins got to it but it had absolutely no spark. I checked the switch wires then the stator. Next in line was the stator. I don't have the equipment to test the PP. so I figured I had nothing to lose to clean the ground. After doing that it had spark, cranked and ran fine. Yes I did check for spark after every step. So in my case I am CERTAIN it MAY HAVE been the problem. Could be an issue with the PP itself as I did remove it and could have jarred a cold solder joint or something. That is why I will replace the PP before long just to make sure.

 

[RoGun_Mako171]

I finally had the chance to remove the bypass covers on the port side (where the compression is lower) and see the rings and pistons look good. The are not stuck and move freely when I turn the flywheel. I do see a bunch of gas/oil pooling at the bottom of the bypass cover. Is that normal?

 

[RoGun_Mako171]

The engine has not been run in 3 weeks and seeing this pooling of the fuel in the bypass covers make me wonder what to do next. Should I focus on the ignition system or go back to the carbs at this point in my troubleshooting of this issue? There is tons of oil/fuel going into the water when this engine idles and it can't be normal.

 

[fireman57]

When you have the carbs off check with a flashlight in the reed valves and make sure something like a small bolt did not get sucked in there. Also look for a bent reed.

 

[RoGun_Mako171]

Thanks for the feedback fireman57, I will take a look at the reeds.

 

[RoGun_Mako171]

I finally took a look at the reeds and there is no screw propping them open. I do see there are some small gaps in some of the reeds that allows light to pass through. Does that indicate a need to replace them?

I decided to keep digging deeper and after taking off the exhaust cover and the heads, I see all pistons have black oil caked on them. It's worse on the lower pistons. The portion of the exhaust I can see in the power head is also caked with black oil. I am meticulous when I measure my 2 stroke oil and there is no VRO. I emptied the boat fuel tank in 2017 and started from scratch when troubleshooting the rich running condition, but it looks to me like the gas must have way too much oil in it to do what I see in the combustion chamber and in the the exhaust (see photos). Is there anything other than excessive oil that would cause that to happen?

 

[RoGun_Mako171]

Could this be the result of weak spark? The spark testing I have done seems to look consistent among all coils, but perhaps it's consistently weak and I just don't have the experience to identify that it is weak. I think it's time to get deeper into ignition system testing.

 

[jimmbo]

You say you are using 50:1. How much oil are you adding to six gallons of gas?

 

[oldboat1]

Have to do them one at a time, but this inexpensive tester will do the trick (available at auto parts stores):

Look for about a half inch sharp spark. Test with all plugs removed.

 

[RoGun_Mako171]

I switched to Pennzoil Marine XLF last season, so I would add 15.4 oz for 6 gallons of gas. I read the directions on the container every time I get fuel and add oil.

 

[Fed]

Out of interest & to rule out any temperature problems I'd shoot the heads with an IR gun to make sure it's getting up yo temp. (145 F ?)
IR guns are very cheap.

FWIW my 1988 90 V4 likes to dribble unburnt fuel/oil with extended running on muffs yet when I return from fishing the exhaust is bone dry and more of a tan colour.

 

[oldboat1]

Could this be the result of weak spark? The spark testing I have done seems to look consistent among all coils, but perhaps it's consistently weak and I just don't have the experience to identify that it is weak. I think it's time to get deeper into ignition system testing.

Spark is measured to test ignition strength -- standard is always much more than plug gap (which is why laying the plug on the block doesn't give you the full story.)

 

[RoGun_Mako171]

I replaced the thermostats and bypass valves the end of the 2017 season because the #1 and #3 cylinders were not getting up to proper temp, but the #2 and #4 were getting to proper temp. The power head is off the engine and in my workshop. It's still winter here in northern Vermont, so it will be a little while before I can retest the temperature of the cylinders.

I do have a spark plug gap tester and have confirmed all 4 cylinders have spark, I think the gap was set to 5/16"when I tested. I could hear a snap, I'm just wondering if it was a loud snap. I ordered a flywheel puller so that I can do a visual inspection of the stator and so I can consider taking apart the crank case to look at the pistons/rings. The #4 cylinder compression has me thinking that since I have it apart this far, maybe I will continue going all the way to replacing the rings or having the cylinder bored out and getting an oversized piston.

 

[racerone]

Rings on # 2 appear to be " trapped " in the grooves.-----Any more close up pictures ?

 

[RoGun_Mako171]

Close-up pics of the #2 & #4 pistons through exhaust ports.

 

[RoGun_Mako171]

Close up pics of the #1 & #3 cylinders through exhaust ports and bypass covers. Since compression was good on these cylinders, I had not paid attention to the rings, but when I try to move the rings, they are partially frozen. The bottom ring on each piston barely moves at all.

 

[racerone]

This motor needs to be taken apart !

 

[RoGun_Mako171]

I thought so. Do you thing there is any hope in bring it back to life for less than $750 in parts or should I consider buying a new engine?

 

[racerone]

These are an excellent running motor once properly rebuilt.-----Do not forget to tear down / inspect / reseal the lower unit-----Be a shame to spend good coins only to find out later that lower unit is no good.-----Most new motors run very well indeed.-----Most can not be diagnosed at home like yours can be.------It also depends on how many hrs you put on a motor in one season.