wet plugs 88 johnson 20hp

[Aar684]

Hi all,



Put brand new plugs in my 88 johnson (20hp) and took the carb off and cleaned it up (no rebuild kit). Ran the motor in the bay for a few hours. Seemed to run very well. Took the boat home and ran the engine with muffs to flush it with fresh water. Wanted to see the condition of the plugs so I took them out. They were wet with fuel and looked well on their way to being fouled.

The fuel I used was freshly mixed at a 50/1 ratio. What could be causing this? Are slightly wet plugs normal? Should I look into a rebuild kit for the carb? I'm lost here. I don't want to replace my plugs everytime I use the engine.

It also idles fine.

 

[petryshyn]

Re: wet plugs 88 johnson 20hp

Plugs will appear wet if you never reached operating temperature just before you removed them. Sound like you didn't since you had only flushed it at last running interval.

 

[Aar684]

Re: wet plugs 88 johnson 20hp

The plugs also looked blackish with some carbon buildup already. Even though they were brand new. What do you think? Carb?

 

[Aar684]

Re: wet plugs 88 johnson 20hp

Ok all, this is it, better explained.

I need some help here. This all started a few weeks ago when I purchased a used engine and boat.

No problems with the boat, but of course with the engine. Day 1 with the engine I changed the lower unit oil, greased everything, and put in new plugs. After running it with muffs in my driveway, I assumed everything was ok. Wrong. I took out the boat into clinton harbor and putted around for about an hour and a half with no problems. After about that long, the motor would lag big time when I tried to throttle up. Once throttled up it would either react slowly and increase the rpms or it would bog down totally and stall. I got back to the launch very slowly.

So I got the boat home, took out the plugs. Brand new plugs fouled after an hour and a half of use. SO, Decided to take off the carb and clean it. Just cleaned it, no rebuild kit or anything like that. Then put new plugs in it AGAIN.

Took the engine out again. This time ran for about three hours, with no problems other than an occassional sputter. Got the engine home and took the plugs out again. The weren't AS fouled but they were well on their way. There was also a little bit of unburnt fuel on them. I can only assume that if I run the motor more the same thing will happen again.

Any suggestions? A complete carb kit rebuild maybe? Bad fuel? What could this be?

 

[psteurer]

Re: wet plugs 88 johnson 20hp

I have a 1989 20hp Johnson. Thoroughly cleaning and then rebuilding a carb can never hurt. If you want to try a quick fix, add 2 oz of Sea Foam per gallon of fuel mix and give your engine a run. If this a new motor to you, there could be quite a bit of carbon built up. Running the Sea Foam gradually through the fuel system may clear out the carbon deposits after a few tanks. Running Sea Foam will not get rid of big pieces of gunk in the carb though. From you post it does not seem like that is your problem though.

 

[Aar684]

Re: wet plugs 88 johnson 20hp

Thank you for the reply. I'm thinking of getting a carb kit and tackling the rebuild. No experience with this though. Not sure if I can handle it.

I actually bought some seafoam yesterday I was meaning to try.

I use penzoil marine 2cycle for mixing with gas. Is that an ok oil to use?

 

[psteurer]

Re: wet plugs 88 johnson 20hp

As far as oil, any NMMA-approved TCW3 oil is acceptable. I am sure Pennzoil has that label. If not, get something that has that label. I always use Johnson/Evinrude oil. I tried the cheaper Super Tech oil sold at WalMart. Seemed to smoke more but that may have been my imagination.

As far as rebuilding the carburetor, it is pretty easy. Check the Top Secret file (top threads on this forum) for how to do it. Be sure to clean out the little orifices (#5 in the process). Also, make sure your idle needle valve has no grooves. If you are going to work on this motor a lot, you need to get a service manual for it. I bought mine on eBay but you can buy them on iBoats I believe. It is good to get an understanding on how these 2 cylce motors work. Sometimes just a tiny adjustment is the difference between getting stuck on the water and getting home

If it were me, I would try the Sea Foam first. It is not a miracle oil but reading your earlier posts you just might need a little bit of cleaning.

 

[Aar684]

Re: wet plugs 88 johnson 20hp

Thanks for the replies everyone.

I will try the seafoam this weekend. I'd prefer not to rebuild the carb if something else is easier (aka seafoam).

I am going to use fresh gas of a little higher octane with a 50/1 mix and see how things go.

 

[tashasdaddy]

Re: wet plugs 88 johnson 20hp

here is the TOP SECRET FILE > http://forums.iboats.com/showthread.php?t=299680

90% of what you need is in it.

1st you have an adjustable low speed jet, mis-adjusted it will cause a rich condition, and the motor not burn all the fuel.

2nd seafoam will not clean a carb, disassemble and kits is the only way to clean a 2 stroke carb. seafoam will keep a clean carb clean.

3rd. when you get thru, do a decarb using the old spark plugs.

Decarb, take a can of seafoam put 3/4 of it in the gas tank, with only 1 gallon of premixed gas. put the rest in a spray bottle. start the engine, and let it come up to temperature. then remove plugs, and them some real good shot of seafoam into the cylinders, replace plugs, let sit 15 minutes. restart, and spray the rest of the seafoam into the carbs, so the the motor almost stalls, wait and repeat until the seafoam is gone.then take for a wide open spin. then put in new plugs, ad premixed gas to the tank, and take it for a wide open throttle spin. it is going to smoke like a house on fire, during this process.