6hp johnson fouled plugs

[notsmart]

so it looks like i put too much oil in the gas/oil mixture. the plugs are fouled so we cleaned them up a bit and tried again to not much avail. i'll try and get new ones and do it again, because it seems that would be best. but in the mean time it seems like where the plugs are screwed in is very dirty as well. does this mean there is still too rich of a mixture? what are the steps i should take to get the engine cleaned out and ready for new plugs so they don't get fouled quickly with the old carbon/oil redidue? also, does it make sense that every once in a while the motor seems to kick in and rev at the expected pace for a few seconds every 5-10 minutes? thanks, all input has been great.

 

[kbait]

Re: 6hp johnson fouled plugs

Read the 'top secret files' sticky at the beginning of this forum. You'll want to check compression, properly test spark, probably do a de-carb, etc. Sounds like its running too rich and intermittent spark.. The top secret files will address those issues and many more. Good luck!

 

[oldcatamount]

Re: 6hp johnson fouled plugs

Sounds like you need a tune-up and a carb cleaning/re-build. Your fuel/oil ratio should be 50:1. What year is the motor?

 

[stevo10081984]

Re: 6hp johnson fouled plugs

i just did my first carb rebuild on a 28hp, the thing would fire but wouldnt idle for more than a few seconds kept fouling plugs i did the same clean..reclean...replace plugs...finially i did the carb rebuild...now it starts easy and runs perfect...easy to do...and change out your fuel lines if it any older than 1990...also easy and insurance on your newly rebuilt carb...good luck

 

[notsmart]

Re: 6hp johnson fouled plugs

Sounds like you need a tune-up and a carb cleaning/re-build. Your fuel/oil ratio should be 50:1. What year is the motor?

it's a '76 and i do believe it is 50:1. would adding just a couple more ounces to 6 gallons make that much of a difference?

 

[oldcatamount]

Re: 6hp johnson fouled plugs

The extra oil won't hurt anything other than fouling the plugs a little bit at low rpm.

 

[steelespike]

Re: 6hp johnson fouled plugs

I would start by checking the spark. The change in idle copuild be a plug cutting in and out.
On a stamdard magneto the spark should jump 5/16.You can get a spark tester at an auto supply.You could run twice as much oil and not affect plug fouling. except if you trolled extensively.Does one plug foul more than another? Does the motor seem strong? Properly setup it should run 10 to 14 mph.

 

[notsmart]

Re: 6hp johnson fouled plugs

Sounds like you need a tune-up and a carb cleaning/re-build. Your fuel/oil ratio should be 50:1. What year is the motor?

can i get one of the rebuild kits at napa or a west marine? or is it something i need to order? thanks so much for the help.

 

[OptsyEagle]

Re: 6hp johnson fouled plugs

Plugs foul because you are either running too rich or running too cold. A little more oil is not going to foul a plug, unless the plugs are 20 years old or something. The first thing to check is if you are running too rich from the carb. Conduct this procedure to ensure your slow speed adjust is set properly.

http://forums.iboats.com/showthread.php?t=167352

The next thing I would check if the above is correct is if you are getting good spark. Use a spark tester and see if your ignition can jump a 3/8" gap.

If it is easy to do, take a look at the thermostat to see if it isn't stuck open making your motor run colder. You also need to ensure that you are using the correct spark plug. You didn't mention the year so I can't tell you which plug, but if the plug is too cold of range, that is a fouling problem there. Lastly if all else checks out, clean the carburetor. Focus on your slow speed jet, but clean everything anyways.

When you resolve the issue you should do a decarb. If carbon was getting on your spark plugs (that is what plug fouling is) you can be darn sure it is getting on your cylinders and piston rings. Here's that procedure.

http://forums.iboats.com/showthread.php?p=2648076#post2648076

 

[notsmart]

Re: 6hp johnson fouled plugs

Plugs foul because you are either running too rich or running too cold. A little more oil is not going to foul a plug, unless the plugs are 20 years old or something. The first thing to check is if you are running too rich from the carb. Conduct this procedure to ensure your slow speed adjust is set properly.

http://forums.iboats.com/showthread.php?t=167352

The next thing I would check if the above is correct is if you are getting good spark. Use a spark tester and see if your ignition can jump a 3/8" gap.

If it is easy to do, take a look at the thermostat to see if it isn't stuck open making your motor run colder. You also need to ensure that you are using the correct spark plug. You didn't mention the year so I can't tell you which plug, but if the plug is too cold of range, that is a fouling problem there. Lastly if all else checks out, clean the carburetor. Focus on your slow speed jet, but clean everything anyways.

When you resolve the issue you should do a decarb. If carbon was getting on your spark plugs (that is what plug fouling is) you can be darn sure it is getting on your cylinders and piston rings. Here's that procedure.

http://forums.iboats.com/showthread.php?p=2648076#post2648076

okay, i do know this. i didn't realize the significance of the slow speed adjust postition and have run it on the "rich" setting for quite a while...goes to show how much i know. with that being known it seems like i'll start on the slow speed adjust steps you've suggested. should i be focusing on anything else other than that in the process? put in new plugs(it's a '76 and i believe i use j6c plugs) and go through those steps? should i be concerned with other issues i may have caused while running it so rich? thanks

 

[OptsyEagle]

Re: 6hp johnson fouled plugs

J6C are the correct plugs. Yes, set the rich/lean knob properly and run it again (always keep a spare set of plugs and a socket wrench in the boat, I always do). After you feel the problem is solved, I would do a proper de-carb to clean out that motor.

The carb adjustment is probably your problem. The reason it probably surfaced now is probably because your water the motor is running in, is most likely a lot colder then it usually is. The water where I live I can walk on and it is not because of my abilities or lack of sin. The cleanliness of the actual carburetor usually creates a lean condition more often then a rich one, so I doubt that was your problem. Hopefully this ends up being an easy fix of just adjusting a knob. Good luck.

 

[JB]

Re: 6hp johnson fouled plugs

does it make sense that every once in a while the motor seems to kick in and rev at the expected pace for a few seconds every 5-10 minutes? thanks, all input has been great.

It makes a lot of sense, notsmart. Your engine is "4 cycling" the rest of the time because the mix is far, far too rich. Get an OEM Service Manual and do the "linkage and synchronization" procedure and set the carb jet controls according to Joe Reeves' instructions in the Top Secret file.

50:1 is the correct fuel mix. Don't mess with it.

J6C is one of the correct plugs; gap them at .030" to .040".

There is probably nothing else wrong except your carb mixture setting being too rich, but if there is it would be something like float setting in the carb too high or something associated with the choke.

Good luck.

 

[notsmart]

Re: 6hp johnson fouled plugs

i'm going to do a decarb on my engine and see if that helps. i've noticed that the "top secret" method is to put liquid sea foam in an extra gas tank and continue with the process. we don't have an extra tank and would prefer not to buy another, so i'm wondering if the spray seafoam would work well enough(the stuff that would be sprayed into the carb and the cylinders). what are your thoughts?

 

[JB]

Re: 6hp johnson fouled plugs

A decarb is never a bad idea, but it will do nothing for your trouble, notsmart. Lean out the mixture.

 

[notsmart]

Re: 6hp johnson fouled plugs

A decarb is never a bad idea, but it will do nothing for your trouble, notsmart. Lean out the mixture.

right on. well, i did both and it didn't seem like not much has changed. put in new plugs and it seems the same as before. someone mentioned that one of the cylinders may not be firing correctly and the residue on the plugs may be an indicator. after putting the new plugs in and running it for a bit, i pulled them out. the upper one had a slight bit of carbon on it and the bottom one had liquid on it. i heard this was indicitive of it not firing correctly, is this true? if so, what are the next pertinent steps from here. or any other thoughts you have on the matter. thanks much.