Update: I finally got all my parts in the mail today. I ordered a new pump housing #590018. Mine was pitted.
I ordered a new gasket #550108 for the pump housing. Mine was ripped.
I also ordered #550107 a new rubber sealing washer for the rear of the pump housing. This keeps the water out of the gears.
As with everything in this cooling system there were odd parts that should not have been there and extra items too! Found an extra o-ring and flat rubber washer, larger than the correct sized one from the manual. I reviewed the manual and parts diagrams and figured out what I was missing and what was worn out and replaced everything. I reassembled the lower unit and new items in correct order. I tested the result with a drill and got only a slight increase.
I Reassembled the lower unit to the head and still no water spitting out the slit. Very disappointed, I tested again with the water hose. It took only a slight pressure and the head would start cooling. But only one cover would stay cool, not the exhaust side.
I decided the pump was not putting out enough pressure because with an increase of hose water pressure I could keep things cool and get water out of the slit. I needed more pressure so, I decided to wrap The eccentric cam with electrical tape. It was my hope this would increase the diameter and the pressure it applied to the sides of the pump housing. This worked amazing. More than doubled the water output. Could I have a bad eccentric Cam or was it worn out perhaps? Knowing this engine, the cam might be homemade. I ordered a new Cam too. #550085.
Very hopeful, with the new water pressure fix, I reassembled everything and tested. One cover stayed cool, very little heat, this was an improvement in cooling but The exhaust side was still burn your hand hot, almost instantly, no change from before.
Drastic measures were needed. I was getting frustrated.
What I know: The cooling water splits in the lower manifold at the bottoms of the motor and goes up each side of the head with internal passages. One side of the head was staying cool, so I decided to bite the bullet and take the cover off the exhaust side that would never get cool. I broke 4 of the 7 cover screws, right at the head, using the impact screwdriver. The cover was hard to get removed. Once I did the problem was clear as day!
See photos below.
This motor must have been left in salt water or something. The Crust and decay was amazing. Almost completely blocked all the passages.
I was able to get the broken screws out with lots of time and heat. This huge blockage was the problem, along with all the random backyard fixes other owners had tried in order to fix the cooling problem. The water was pumping up into the head but taking the path of least resistance. All my fixes improved the flow and pressure but not enough to get through the blockages, Never cooling the exhaust side. There is water flowing behind this exhaust cover and fire too!
I need to find at least 4 cover screws. Can anyone help me with that? I can’t find them.
What is the best method to seal this cover back on? There has to be a method.
I noticed my eccentric cam was not as eccentric as the original offerings on eBay so I’m sure that was a huge part of the pressure problem as well. Frank you might have spotted this early on and commented on the extra daylight seen in my first pump photos. I think the cam was home made or badly worn out somehow.
