97 Outboard C90 Water on Plugs

[msd58]

See explanation below pics My C90TLRV started to run rough. As if running out of gas. After eliminating the possibility of water in fuel or bad fuel I did a compression check and the middle and lower plugs are clean but I can see water droplets on the plugs. Top plug looks better but I can see tiny water droplets too. I have attached a pic of the compression plus also. Motor starts right up but runs very rough and stalls. Looking for ideas. Head gasket? Side exhaust plate? Ran great all summer. ​

 

[99yam40]

are we supposed to guess what the compression #s were?

 

[msd58]

are we supposed to guess what the compression #s were

Top plug was 105, middle was 120 and bottom was 120

 

[99yam40]

do a leak down test with compressed air and see where air leaks to.
but if all 3 have water signs I would guess the exhaust plate corroded thru.
time to open it up and look

 

[msd58]

do a leak down test with compressed air and see where air leaks to.
but if all 3 have water signs I would guess the exhaust plate corroded thru.
time to open it up and look

Thanks! Yes all three plugs have signs of water.

 

[msd58]

Here's a new twist. I pulled the spark arrestor off this AM and the bottom was filled with a milkshake!

 

[99yam40]

I am confused on what a spark arrester is on a premix 2 stroke motor

 

[racerone]

I think he is referring to the intake air silencer.

 

[msd58]

I think he is referring to the intake air silencer.

Sorry wrong terminology. It's the air intake silencer that had the milkshake in it.

 

[msd58]

Update. Hole found in upper end of inner exhaust plate

 

[racerone]

Corrosion issues on these motors is no surprise to me.

 

[msd58]

Corrosion issues on these motors is no surprise to me.

Not bad for a 1997 I think. I read where some newer models than this in four stroke had some pretty widesprrad corrosion. 4 stroke motors.