18 hp 1966 Fastwin - Forward bearing issue

[Grantspec]

I just got my fastwin all put back together and the gremlins seemed to be sorted. All freshly painted and she looks beautiful. It was running great for the first tank of gas (22 mph on my 14 ft fiberglass jon boat) then it started losing top end after about 60 seconds at WOT. After idling for a while it would get up on plane and then start losing rpm again. I checked the thermostat and it was fine (plus its brand new). No obvious clogs in the cooling system. Water was flowing out of the exhaust relief. Impeller is brand new as is the impeller housing and impeller plate. So I began to suspect the gearcase (which I disassembled and resealed). When I drained the oil it looked to have fine bronze particulate in it. I split my freshly resealed case and found no obvious damage. However, I noticed that the alignment dowel for the forward bearing has been sheared off and the forward bearing does not even have a hole for the dowel. It was this way the first time I tore everything down and im afraid i did not orient the front bearing correclty when I reassembled. The forward bearing that was in there has a keyway in it but no alignment hole like the prop side bearing does. I am beginning to suspect that the forward bearing is the wrong part? I have attached pictures of the bearing and the sheared off dowel pin. Any one have any insight on this? Also, What should I do about this stupid sheared dowel pin? I have put a ton of time and effort into this motor and i am reaching the point of giving up. Thanks to all that help out on this forum.

You will notice in the pictures where the sheared off pin has dimpled the forward bearing. The thrust surface between the forward bearing and the forward gear seem to be quite worn (i think this is where the fine bronze particulate is coming from).

 

[Grantspec]

Anybody ever seen this? After looking up the part numbers it seems this style bearing is a replacement for the original with the alignment dowl?

 

[racerone]

The dowel locates in the slot ( keyway ) ---It is located to line this bearing up for proper oil flow for lubrication.---This is oh so common to see the pin pushed in by careless assembly, Can't remember how many times I have seen that since 1968 on these lower units.-----Just install a new pin close to the old one.----Did you fill gearcase from bottom till oil came out the vent hole ?

 

[Grantspec]

Yes I did, there didn't seem to be any leaks in the lower unit either as there was no water, just bearing material :facepalm:. Thanks racerone for the input. I'm thinking I will put a new dowel in and put her back together to see what happens hopefully the bearing and gear thrust surface is not too far gone.

 

[F_R]

I'd be careful to take a good look at that gear & bearing. If there is too much wear, the gear teeth mesh becomes too loose, possibly shearing all the teeth off eventually, if it is bad enough. In later years, OMC improved on the design, putting roller thrust bearing in there. Older motors can be updated at a $tiff price.