'73 Johnson 25hp Powerhead Gasket Kit - Nylon Washer?

[OldOMC31]

I recently inherited my grandpas 1973 Johnson 25hp outboard (25R73A). Issues I was having similar to bad upper crank seal. Upper seal was good but had a leak where the lower crankcase half seals to the block. I have the anaerobic sealer to repair this. I have bought the powerhead gasket kit and head gasket with a new sets of piston rings to complete the rebuild. Currently everything is taken apart and starting the cleaning and measuring tolerances. The question I have is where does the small nylon washer that is included in the powerhead gasket kit go? I cannot seem to find it anywhere looking at parts diagrams, my service manual and scouring the motor. I have attached a picture of what I am talking about. This is the first post I have made on here but have used this forum countless times so far during the my preparation to take on my first outboard rebuild. Thanks to everyone for the excellent content I was able to find from lower unit topics to powerhead topics to specific adhesive and sealing products. There is tons of great information on here and I know it helps a lot of people. Thanks in advance for any information!

 

[F_R]

No idea. Is that an OEM kit or an aftermarket kit? Kit part number?

 

[OldOMC31]

OEM Kit - Part Number 0384960. Ordered from Crowley Marine which didn't show a picture. Found the above picture online. Actually the kit arrived a few days ago and came with everything in the picture plus upper crank seal, the upper and lower roller bearings external o-rings, and the carbon seal o-ring. Still stumped as to what the nylon washer is. Looks small enough to be used somewhere near the fuel pump but it doesn't look like it belongs anywhere.

 

[F_R]

Still no clue. Is it a washer with a hole in the middle? Only thing I can think of is for the drain plug on the carburetor. Odd that they would put that in a powerhead gasket set.

 

[OldOMC31]

Yes. Photo of washer attached. marker included for size reference. Ill check carburetor tonight to see if it could go there.

 

[F_R]

I got it. #93, used on previous years' models.

 

[boobie]

Naw.. It's a drain plug washer for a gear case that got mixed up in the power head gasket set.

 

[F_R]

Wanna bet?

 

[boobie]

Yah !

 

[OldOMC31]

Nylon washer is thinner, smaller ID and OD than the two gearcase drain plugs. I finished the powerhead reassembly and still have that washer left over! I have everything else put back together. Will test in barrel today or tomorrow. If everything seems good, lake test this weekend. FR, what year and model did you get that photo from? I tired looking at all the different years that the gasket kit (Part Number 0384960) fits according to boats dot net and could not find one matching the photo you attached to your post. Thanks.

 

[F_R]

That drain fitting was used 1968-1969-1970 18-20-25hp,.I doubt they would assign a different gasket kit number just for that little washer. It fits over a" bolt, right?

 

[OldOMC31]

Taking a closer look at the photo, it looks like #93 is going over a nipple. My '73 motor has the covers installed where the nipple is on the top bypass cover and fuel pump on lower cover. The hose from upper bypass nipple comes from lower nipple on intake manifold. I assume this is done to divert excess fuel or crank gases and burn it in top cylinder? Washer looks to big to fit between nipple and bypass cover. I agree it looks like it should fit over a bolt. Guess ill just have to see how it runs! Thanks for the help.

 

[F_R]

Dagnabbit, I know what I'm talking about. Up through 1967 the 22 cubic inch motors had crankcase drains that dumped raw fuel into the lake. Bowing to environmentalist's pressure, in 1968 they eliminated half of the drains and dumped the remaining drainage into the exhaust stream via that hose nipple. The hot exhaust was supposed to evaporate the outflow. It sort of worked, but the motors didn't run as well because of the eliminated drains. Starting in 1971, the drain hose was re-routed to the upper bypass cover for direct injection into the cylinder, where it was supposed to burn. All it really did was make the upper cylinder run richer than the lower cylinder. A big mistake because the motors ran like crap, compared to pre-1968. Imagine the feedback we got from customers that traded n their old pre-1968 motors for a new and "improved" 1971-up.

BTW, the lower corner bolt hole was drilled through into the exhaust and the stock bolt was replaced with that special nipple to accomplish the 1968-70 design.

 

[OldOMC31]

Thanks for the help! That washer would fit perfectly over a 1/4-20 bolt, or as you describe above, the nipple to the bypass cover. Tested the motor in a barrel last night and made slight adjustments to the low speed needle. Original issue of crank pressure escaping between block and lower crankcase cover is fixed. It runs great now!

 

[Willyclay]

Attaboy!