Spark Plugs

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
I'm confused, all the research indicates that these numbers are good and rules out worn rings and piston problems ... ??

Extract from this article http://www.mhnetwork.com/news/proper...gine-problems/

Wet Test - With the spark plug removed, squirt about one teaspoon of oil into the spark plug hole. Take a compression reading and observe the difference between the wet and dry tests.
  • Readings from the wet test should not increase by more than 10 percent, cylinder to cylinder.
  • If the compression increases with the wet test, the results identify the problem as the piston rings and/or cylinder walls. The theory behind this test is that the oil is providing a wet seal for the rings. If they are not sealing on their own they will when the oil creates a seal and an increase in compression will be observed.
  • If the compression stays the same, the results point to the valve train. The theory is that when the rings are sealing, the oil will have no effect on compression and therefore the valves are most likely the cause of the problem.
Chris.......
 

zul

Petty Officer 1st Class
Joined
Aug 24, 2015
Messages
235
Sorry, that would be 'Cold and Dry' followed by 'Warm and Wet'.

Heading for fresh oil and an oil additive. I have a good recomend on BG oil add products ... Band aid? Yes, I know. So, if I were to wipe up after the blow by and continue running the motor with oil additive .... the result would beee ??? Just trying to get a feel for how long I can limp things along and what the consequences might be??!!

Option #2: Rebuild for $3,000

Ugh, again.

zul
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,786
What's your goal here? The engine is healthy enough to run, and there's nothing catastrophic about your numbers. However I still don't think your results are valid; you need warm and dry followed immediately by warm and wet.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
What's your goal here? The engine is healthy enough to run, and there's nothing catastrophic about your numbers. However I still don't think your results are valid; you need warm and dry followed immediately by warm and wet.

This...

Compression results from a cold engine are worthless. Total meaningless and absolutely not valid to make any conclusions on.
 

zul

Petty Officer 1st Class
Joined
Aug 24, 2015
Messages
235
Can I do a 'warm and wet' test right now? Does the 2-stroke oil I put in there need to burn off?? If you think that I can do the warm and wet, I can do that in a few days ... followed by the warm and wet as suggested.

If there is any good news running around, I am getting really good at pulling and installing spark plugs ;)
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
The oil in the cylinders will take a little time to burn off. Probably about 5 minutes under load, but on the flushed. ... I would let it idle for about 20 minutes. Keep an eye on temperature and oil pressure. Then do your 'warm and dry' test. ..

Chris. ...
 

nola mike

Vice Admiral
Joined
Apr 22, 2009
Messages
5,786
You already have the 'warm and wet' results.

Yeah, his results and descriptions of them are confusing; repeating the warm 'n wet right afterward would eliminate some potential variables. Maybe keep him from having to do them *again* (especially if his warm 'n dry readings are higher than his previous warm 'n wets...)
 

zul

Petty Officer 1st Class
Joined
Aug 24, 2015
Messages
235
Yesterday = New oil, New oil filter. Plus BG oil additive.

Finally got the day to do the Warm & Dry test:

#1 135
#2 130
#3 135
#4 135
#5 130
#6 130

I think that these are my best numbers yet, but ??
I mean, these aren't 'new boat numbers' but for a 1994 with 410 hours, I should be pretty happy?
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Now, put your new spark plugs in, button it all up and go annoy some fish. ... :D
 
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