1993 Johnson 225 Fouling Two Plugs

[Boatingdobbins]

My '93 Johnson 225 has a miss that can be heard at idle. Motor also won't stay running under 1200 rpm. Have completed the following:
1. All new plugs.
2. New water separator filter and inline filter under cowling. Cut open inline filter and did not find any debris.
3. Hooked up portable tank to engine to isolate main tank as problem.
4. Completed compression check all cylinders equal at approx. 85 psi. No change from test completed several years ago.
5. Hooked inductive timing light to all cylinders and all seem to be getting spark.
6. Opened carburator drains and drained gas. Drained through a white shirt and did not see any debris.
7. Inspected all vacuum hoses and gas supply hose for holes or disconnection.
8. Swapped power packs with spare.

Motor is fouling the two top port plugs. Plugs have a heavy carbon build up. Bottom port spark plug and all starboard are firing clean.

Looking for advice on what to check next. Thought about swaping coils around but seem low chance to have two bad coils. Running out of options before being forced to take it to a professional.

 

[jonesg]

Re: 1993 Johnson 225 Fouling Two Plugs

Go to autozone and buy an adjustable spark tester, set the gap to 7/16th inch and get after those cyl's that aren't firing.
I suspect you'll find yellow or no spark, it needs to be blue spark.
A timing light will not show spark quality and you cannot test for spark strength with a sparkplug, the gap must be almost 1/2 inch.
Spark testers are very cheap and useful , $12.

Then swap coils, inspect the bad ones when removed, turn them over in your hands and look for cracks, if cracked they're shot. Inspect where they mount is clean and shiny for good grounding.

Swap the spark plug wires seperately so you can isolate it to bad coils/grounds or plug wires.

If the problem doesn't follow the coils or wires, its likely to be power pack time but thats only a guess, to be certain you need a peak reading meter, or take the chance and buy a pack.
http://cgi.ebay.com/ebaymotors/ws/e...viewitem=&_trkparms=clkid=8660284704786060122

When I did this it all pointed to the PP so I bought one and it fixed the problem.

 

[ezeke]

Re: 1993 Johnson 225 Fouling Two Plugs

First thing I would do would be to perform a thorough de-carbon treatment using the schrader valve on the primer solenoid and an aerosol product such as sold by most outboard manufacturers. You will need the $2.00 adapter #0763644. BRP Engine Tuner works well. Plan on several treatments if you have not been doing this annually.

Follow that up by servicing your recirculation check valves; they are probably already fouled, but definitely will be after a de-carbon treatment.

Loopers hate running cold, so be sure that your thermostats are functioning properly.

Ignition coils can test well and still break down when warmed up. They can also fail to perform well if the ground is corroded, so removal and cleaning of the base is a good idea.

Be sure that you have the recommended spark plugs and spark plug wires.

http://shop.evinrude.com/dyn_prod.php?p=763644

 

[seahorse5]

Re: 1993 Johnson 225 Fouling Two Plugs

If you are in a salt water area, there may be corrosion underneath the coil mounting ears which is also the ground. Check the resistance through the plug wire and caps, there should be none. Check carbs to make sure they are not flooding, have the correct float height adjustment, correct jets and mixture settings. Check cylinder head engine temps to make sure the thermostats are warming the motor up correctly.

 

[Boatingdobbins]

Re: 1993 Johnson 225 Fouling Two Plugs

Bought a spark tester. Spark jumps a 1/2" gap on all cylinders. Currently believe two of the carbs have some fouling. Planning on having a professional rebuild the carbs. Will post the final outcome.