NEED ADVICE: 1983 Evinrude 9.9

[CaptainOfTheMinnow]

Hello iboats community! This is my first post here. I am looking for some advice regarding my 1983 Evinrude 9.9 (w/ 15 hp carb) that pushes a 14 ft Flatbottom.

The history in the motor is it has been my fathers since new and sat for many years until I rebuilt the carb, replaced fuel lines and plugs several years ago. I’ve never had any problems out of the motor after rebuilding the carb and I always ran fuel out of bowl when storing.

Last week I was out on the lake for about 10 minutes when she suddenly died from WOT. No issues prior to dying, ran smooth maybe a little smoky from rich mix, but nothing out of the ordinary. When it died from WOT I took the cowing off and could tell the motor was HOT. I could hear water sizzling. Again, I was only out on water 10 mins at most when this happened.

Got home and rebuilt carb and put fresh gas, no luck. Carb was clean and bowl was full of fuel. Next I put new plugs Champion (821) OEM L77JC4 or something like that, gapped to .30 no luck. Verified spark on both cylinders with spark tester and see visible spark. Should mention Old plugs were not fouled and gapped appropriately.

Synopsis: She has fuel and spark but won’t fire. I am hesitant to buy or rent a compression tester because the Armstrong starter tells me there is compression similar to what it has always had previously. I did not verify pee hole flow on this particular day because I had just put the boat in the water, but historically always had water coming out. ANY IDEAS? I APPRECIATE YOUR TIME!!

 

[flyingscott]

Sounds like your waterpump went out. Do a compression test?

 

[CaptainOfTheMinnow]

Sounds like your waterpump went out. Do a compression test?

Thanks Scott. I believe compression test is the next thing in order. I too fear the water pump maybe failed and caused the overheat. I will post results of compression test later today. :yo:

 

[racerone]

These motors need a new impeller about every 5 / 6 years.----Many folks learn the $$$$$ way that these motors will run to destruction .----There is no shutdown feature to stop the motor should it reach critical temperatures.

 

[CaptainOfTheMinnow]

These motors need a new impeller about every 5 / 6 years.----Many folks learn the $$$$$ way that these motors will run to destruction .----There is no shutdown feature to stop the motor should it reach critical temperatures.

Thanks for the comment. I will post results of compression test later today. Was only on water for 10 mins but she is 40 years old and likely tired.

 

[flyingscott]

10 minutes is 8 minutes to long.

 

[Geoffrey Graydon]

10 seconds can be too long without water,first thing to go is your pump impeller and things just go downhill from there.I hope you didn't do too much damage and the motor isn't ruined.

 

[CaptainOfTheMinnow]

Compression Test Results:
Top: 35 psi
Bottom: 58 psi


:violin:

Does this mean a powerhead rebuild or ring job at a minimum is going to be required to get her going again? New water pump/thermostat would be included to that list as well.

 

[racerone]

This does not sound good.-----Just 6 bolts and cylinder head is off.----Time to inspect cylinder walls !

 

[CaptainOfTheMinnow]

This does not sound good.-----Just 6 bolts and cylinder head is off.----Time to inspect cylinder walls !

Yep, next step will be pulling the heads. Fingers crossed.

 

[CaptainOfTheMinnow]

Need advice with how to remove stubborn head gasket material. Is there something I can soak the gasket in? It is probably original and has deteriorated very badly and is glued to block from heat or years of use.

Pulled head and found what I believe is broken rings on top ringlands for both pistons. Bottom one isn’t as loose, perhaps accounting for better compression on that cylinder. I will try to post pic below. Significant carbon buildup, light scoring on pistons (I think?)

 

[CaptainOfTheMinnow]

[No message]

 

[CaptainOfTheMinnow]

What works well for removing stubborn gasket material? Some sort of solvent perhaps?

 

[hardwater fisherman]

Did you remove the head or just the bypass cover?

 

[CaptainOfTheMinnow]

Did you remove the head or just the bypass cover?

Thanks for the reply, I just realized I had removed bypass cover thinking it was the head. I’ll pull the head today. New to two strokes..

 

[CaptainOfTheMinnow]

Pulled head and cylinder walls look good. Pistons appear okay, but lots of carbon buildup. Any reason to replace piston vs re-ring if they look okay when I pull them out? Will try to post pics later. Opinions welcomed..curious how best to remove water deposits within block around cylinder walls? Thanks to all.

 

[CaptainOfTheMinnow]

Pulled head and cylinder walls look good. Any reason to buy new pistons if the old ones look okay once I Have them in my hand? Lots of carbon buildup. Will try to post pics later. What’s the best way to remove buildup around cylinder walls within block? Thanks to all.

 

[CaptainOfTheMinnow]

[No message]

 

[racerone]

Any pictures of both sides of the head gasket ?----Were the head bolts tight ?

 

[CaptainOfTheMinnow]

Any pictures of both sides of the head gasket ?----Were the head bolts tight ?

I’ll try to grab some pics tomorrow. Head gasket looked pretty good and yes, bolts were tight. Head gasket came off easily in one piece vs the nightmare on the thermostat cover and bypass cover lol. Thermostat had no FOD, just water corrosion.