Minute amount of water on plug.

[towboater1]

I have a Mercrusier 140 we took it out this past weekend and she seemed to run fine,had the carb. rebuilt last Monday.After returning home I figured I'd do a tune up as I just felt it was time for one...seemed to be running just a bit rich.Cranked it up this morn.let her run for awhile on the muffs then when I pulled the plugs I noticed on the #3 plug a slight bit of water? I know your not supposed to have ANY water on a plug... Any ideas what might be the cause? I mean a small amount like 2 little spots maybe not even the size of a pin head..

 

[Don S]

Re: Minute amount of water on plug.

If you have 2 drops on the plug, think of how much more is in the rest of the cylinder. Is the engine running smooth? Have you done a compression test? A leak down test looking for bubbles in the cooling system may be in order.

 

[towboater1]

Re: Minute amount of water on plug.

Engine runs great,compression test showed 130 0n #1,120 0n #2 120 0n #3 and 130 on # 4 cylinders.It's not much water at all,I noticed it when I was looking at the plugs closer.

 

[achris]

Re: Minute amount of water on plug.

What year is the engine? When was the exhaust elbow last replaced? Any water, even a couple of pinhead sized drops, is an indication that something is wrong. You have been diligent enough to find it before it's done any further damage. So let's find the source and save you a ton of money...

 

[towboater1]

Re: Minute amount of water on plug.

I got the boat from my uncle,I think the engine is an '87 model.He had everything out last year and he only took the boat out once.Mom and his other sister talked him into selling due to his age(87 and went alone).He took good care of the boat,I will try to find out and did deeper.. Thanks Don and achris.The wife and I talked about just doing a complete overhaul..

 

[achris]

Re: Minute amount of water on plug.

If you can get the engine and leg serial numbers we can give you an exact year. They will be the number '0' followed a letter (probably 'B') followed by 6 digits. Sounds like your uncle was as anal as I am... I would hold off on the 'overhaul' just for the moment, it could be something relatively simple and inexpensive (if 'boat' and 'inexpensive' can be used in the same paragraph!)

Chris.......

Here's a link to some useful info (manuals) you've going to need...

Engine -> http://www.4shared.com/document/hh5Z9V47/Service_Manual_10.html
Drive -> http://www.4shared.com/document/zz_5pj9o/Service_Manual_06.html

 

[scoflaw]

Re: Minute amount of water on plug.

Might be going out on a limb here, but is it not completely possible that a warm plug could attract condensation from the cooler water in the manifold , with an open exhaust valve?

 

[achris]

Re: Minute amount of water on plug.

Might be going out on a limb here, but is it not completely possible that a warm plug could attract condensation from the cooler water in the manifold , with an open exhaust valve?

let her run for awhile on the muffs then when I pulled the plugs I noticed on the #3 plug a slight bit of water

Any water detected under those circumstances needs to be investigated. For the cost of an exhaust elbow gasket he can have peace of mind, or know he needs to replace it (elbow and/or manifold)....

 

[towboater1]

Re: Minute amount of water on plug.

Engine serial # is as follows...6044966
Transom Assembly Serial #...6034781
Stern Drive Unit Serial #...6014644

 

[RogersJetboat454]

Re: Minute amount of water on plug.

Might be going out on a limb here, but is it not completely possible that a warm plug could attract condensation from the cooler water in the manifold , with an open exhaust valve?

Goes the other way chief...
Moisture condenses against cold. Ever notice your toilet tank sweating in the summer time?

 

[scoflaw]

Re: Minute amount of water on plug.

Goes the other way chief...
Moisture condenses against cold. Ever notice your toilet tank sweating in the summer time?

Exactly, and the moisture collects on the warm side. Same thing, on an uninsulated house window, in the winter. Moisture on the warm side. The name is Mike, by the way.

 

[RogersJetboat454]

Re: Minute amount of water on plug.

Exactly, and the moisture collects on the warm side. Same thing, on an uninsulated house window, in the winter. Moisture on the warm side. The name is Mike, by the way.

The warm moist air condenses against the cold surface. Ever see how a dehumidifier works, or any refrigeration unit for that matter? There is a reason that there is a drip tray or drain under the cold side (evaporator).
On the other hand, fire up a heat gun and hold it over a piece of bare metal. You will see the moisture in the pores of the metal rise up and evaporate.
Warm/Hot surfaces drive moisture away Mike...

 

[achris]

Re: Minute amount of water on plug.

Exactly, and the moisture collects on the warm side. Same thing, on an uninsulated house window, in the winter. Moisture on the warm side. The name is Mike, by the way.

The warm moist air condenses against the cold surface. Ever see how a dehumidifier works, or any refrigeration unit for that matter? There is a reason that there is a drip tray or drain under the cold side (evaporator).
On the other hand, fire up a heat gun and hold it over a piece of bare metal. You will see the moisture in the pores of the metal rise up and evaporate.
Warm/Hot surfaces drive moisture away Mike...

Hey guys, maybe I can settle this. 2 situations I get into.
1) I work in SE Asia a lot. I work inside, in air-conditioning for a while, then I go outside, nice and humid and hot. My glasses fog instantly. Moisture from the warm air hits the cold glass and condenses.
2) Currently in Italy for our annual skiing holiday. Walk around outside, glasses get nice and cold, walk into a warm shop or hotel, glasses fog instantly. Moisture from the warm air hits the cold glass and condenses.

Chris......

 

[achris]

Re: Minute amount of water on plug.

Engine serial # is as follows...6044966
Transom Assembly Serial #...6034781
Stern Drive Unit Serial #...6014644

Engine model number 01406002 - 1982

So the manuals I posted (based on it being 1987) are the wrong ones. Here's the right ones...

Engine -> http://www.4shared.com/document/M35B2RL4/Service_Manual_03.html
Drive -> http://www.4shared.com/document/wPl4tS8_/Service_Manual_04.html

HTH,

Chris........