1997 7.4 Bravo sea water pump question

[DownByTheRiver]

I've been searching for the reason my boat keeps dying intermittently, and I think I found the problem.

I initially started this thread:

http://forums.iboats.com/forum/engi...er-30-minutes-starts-after-sitting-dies-again

But now the boat won't start at all. I got her home, and pulled the seawater pump/impeller/fuel pump (terrible engineering btw) assembly. Attached are pictures of what I found, with the old and new fuel pumps for reference. The fuel pump lever has been ground down, due to the seawater pump being BONE dry. No fuel in the cavity with the cam lobe, bone dry completely.

The cam shows wear, but I don't think it's so bad that it can't be reused. The seal on the shaft is perfect, and the shaft has zero play. The boat only has 110 hours on her, and the impeller looks brand new. If I turn the water pump so that the pulley is down, the cam will move with gravity, along the shaft. There's seems to be a washer (towards the impeller side) that's loose too. Is this normal? The cam free spins with a finger, and spins normally when I turn the pulley, with no noises...it just appears to have some side to side movement.

http://i378.photobucket.com/albums/oo229/kremsTW/20160702_183848_zps5ylff3jj.jpg
http://i378.photobucket.com/albums/oo229/kremsTW/20160702_183901_zpsr87bb9wi.jpg
http://i378.photobucket.com/albums/oo229/kremsTW/20160702_191226_zpsheyofqzo.jpg
http://i378.photobucket.com/albums/oo229/kremsTW/20160702_191236_zpstxyjonga.jpg

 

[tpenfield]

My boat engines have those combo fuel pump sea water pump. Mercruiser did not keep with that design very long, if I recall. I would go for a new fuel pump and make sure you have the proper lube and that it does not leak, etc. and see if it works.

I would think the cam should be affixed to the pulley shaft, but other may have a comment regarding that aspect of the issue.

 

[Bondo]

Ayuh,.... That cavity is supposed to be full of oil ain't it,..??

If the cam ain't connected to the shaft, it ain't gonna actuate the fuel pump,....

 

[DownByTheRiver]

Absolutely should be full of merc gear lube. What's weird is that when I spin the shaft, the cam turns normally. When I spin the cam with my finger, it spins indendantly of the shaft...???

Should I install the new impeller and fuel pump that I've got sitting here and see what happens?

 

[mr300z87]

I recently replace seals in one of these pumps and had it completely apart. If memory serves me correctly there is a bearing cup that actually rides on the cam, which is what I think you mention is spinning independently. I would put it back together with gear oil and give in a try. These pumps are big dollars.