Mercury 60HP 1990 valve type bearing reeds????? WHAT?

dieseldan

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Nov 15, 2020
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4
I'm in need of some advice on a 60 horse motor I've been running for the last 6 months or so.

First major issue I have is I can not find a service manual for this motor anywhere!!!! 0D000298. A manual does not seem to exist for this motor. This is a 3 cylinder motor with 2 carbs.

Have had some fuel leaking out and noticed it on the waters surface. really hate seeing that. Found the fuel pump to be leaking and planning on replacing gaskets with a kit. Also upon some tune up work noticed the lower carb does seem to spray some fuel outwards while starting and warming up. Runs like a scalded dawg wide open and doesn't seem to spray. Hoping a general clean up of carbs fixes this issue. This issue along with some occasional back pressure being blown out and bogging down made me think hey probably not a bad time to throw some new reeds in while im at it. Well seeing on the parts diagram it appears the reeds are a style I have never ever seen before. Would require full tear down to replace it seems. My question is are these reeds typically more durable than the typical style found directly behind carbs?

I absolutely love this motor. It is a torque monster. I really want to do everything I can to take care of this motor. I'm mechanically inclined and fairly familiar with outboards, but not aware of the service points and things to check out on this particular motor without a service manual. Any advice you may have is greatly appreciated!

One more bit. Bought this motor and it looked nearly new. 145 psi on all cylinders. I have probably put 75 hours of use on it in the 6 months ive had it. good oil at 40:1 and non ethanol. I'm now at 110 psi on all 3. Runs strong but I really was shocked to see such a change in compression. Typical for the amount of use or was this just needing broke in? IMG-1969.jpg
 

racerone

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Dec 28, 2013
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38,972
That change in compression needs to be investigated.-----Remove bypass cover/s to look at pistons and rings.----That style of reeds was used on Mercury motors since the early years ( late 1940's and 1950's ) and are quite reliable.----And reed valves have nothing to do with compression in the cylinders either.
 

dieseldan

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Nov 15, 2020
Messages
4
That change in compression needs to be investigated.-----Remove bypass cover/s to look at pistons and rings.----That style of reeds was used on Mercury motors since the early years ( late 1940's and 1950's ) and are quite reliable.----And reed valves have nothing to do with compression in the cylinders either.
Replaced the water jacket/exhaust manifold gaskets a couple of months ago. cylinders had cross hatching still and no abnormal scoring on pistons that I could see from the side I had a view to. Aware that the reed valves have nothing to do with compression but they do have a role in keeping air from being pushed back out thru the carbs. One way valve from the crank case. with the occasional symptoms of air being pushed back thru the carbs only made me think that a failing reed could be suspect.
 

Faztbullet

Supreme Mariner
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Mar 2, 2008
Messages
15,933
cylinders had cross hatching still
Means absolutely nothing ..cylinders can be worn pass limits and still have hatching. The manual is 90-817643-1
 

Fun Times

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May 16, 2009
Messages
9,241
That is not the correct manual. That works for 0D0000750 and up.
Merc manual part # 90-86135--5 / 1-593 Covers engines:
45 & 50 (4 Cylinder) 50 & 60 (3 Cylinder, 2 Carburetor)
AND 70 (3 Cylinder, 2 Carburetor)
(U) 4576237 and Above (A) 8042650 and Above (B) 9136250 and Above (C) 7088598 and Above
(U) 4571652 thru 6428681 (A) 8042350 thru 8074512 (B) 913582 thru 9392276 (C) 7087823 thru 7208333


 
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