Spark plugs fouling out

[LOUEG]

I have a 1963 MERC. 500. My plugs keep fouling out. When I clean them it will run for abot 5 min. I then clean the plugs and it will start It does seem to be missing while it is runnig. The one plug is real clean.I want to bring it into the shop but I'm afraid it is major and being a 63 is it worth it. Could it be bad plugs or wires?? What else could cause this???? <br />The one plug is clean as when I put it in 6 months ago. It to gets fouled out.

 

[slow_boat]

Re: Spark plugs fouling out

How many carbs on this engine? Done a compression check?

 

[LOUEG]

Re: Spark plugs fouling out

It has 2 carbs. I haven't done a compression test yet. If one of the cilinders is not working how much should I expect to pay. Could this be the cause of my problem?

 

[rickdb1boat]

Re: Spark plugs fouling out

One plug being "Real Clean" indicates you have water getting into that cylinder and "Cleaning" the plug. May have a blown head gasket or worse. As slow_boat said, do a compression check before you go any further! Let us know the readings of the test. Good Luck.

 

[slow_boat]

Re: Spark plugs fouling out

How clean is 'real claen'? If you are using the term 'real clean' relative to the 'real dirty' plug, you may not have a blown head gasket. If it is indeed 'real clean', as in appearing new, it probably does mean it is being water washed (not too good...new head gasket at least). On the other hand, if it appears like a clean *used* plug, you could have low compression on the fouling cylinder (various reasons, none good), or maybe even the carb for that cylinder is running way to rich a mixture to it & thereby fouling the plug (not too bad). Hope for the carb being the problem. FWIW, there are ignition problems (weak spark) that can cause fouling on only one plug. Always start with a compression test!

 

[LOUEG]

Re: Spark plugs fouling out

I did a compressoin test on 3 of the 4 cyl. The 4th cyl. I was unable to reach with the tester. The fireing order is on the moter 1-3 then 2-4. I was able to get a read on 1&2 of 80lbs psi. I would get 80lbs and then it would lose pressuer. I didn't think that should happen. I'm usually wrong. On the third cly. I could't even crank the engin it was like frozen. I tried with the key and then manually. The 4th cyl I couldn't reach with the tester. This cyl. was the one with the clean spakrk plug. The out side of this plug was rusted and the guts of the plug were pretty clean but did have some resion on it, telling me it was warking at some time. If I put all the plugs in and try to start it with only the 4th plug hooked up should it start. What woud cause one cyl. to freeze up.

 

[rickdb1boat]

Re: Spark plugs fouling out

^

 

[LOUEG]

Re: Spark plugs fouling out

I figured out what the problem was with the third cyl. was. It was the tester. The shaft on the tester was hitting the cyl. and was unable to move. I put new spark plugs in and it ran in idle for ten minutes. I then checked the plugs and thay did have some fuel on them. It wasn't alot only a few drops on each. While the boat was running I did notice fuel/oil in the prop exhaust. I have been using a 50:1 mix. This is what the person who sold me said he was using but, he could be wrong.I thought it was alot of oil but then again I wasn't even born when my motor was.