Yamaha 90 HP TLRY Peeing Weakly After Complete Water Pump Rebuild

[yammiemark]

Trying to understand what I am looking at after I bought a used outboard and got it running. When the 90 HP TLRY is running, it has a weak stream of water coming out of the head. This is after I replaced the entire water pump assembly including the base plate that has the drive shaft bearing seals underneath it. What perplexes me is that there is a strong stream of water coming out of the front of the bottom of the outboard squirting out in between where the mid-section meets the gear case. Note, I did replace the damper seal underneath the screwed down grommet located on the top of the pump housing. Appreciate any thoughts to help me figure out this problem.

[99yam40]

I would use some compressed air to blow up the Tell tail hole to make sure it is not restricted with debris.
while running on muffs even.
might move something around and get a better stream.

[DennisG01]

Can you confirm that the stream was stronger before you replaced it? Also that you were using the SAME hose? Otherwise, it may just be the way your engine is on your particular hose. How is it in a bucket or in the water?

[yammiemark]

Just a quick update....I took the exhaust cover off, and it looks like the former owner sucked up mud with some other crap. The cooling passages on the exhaust side have mud in every nook and cranny. Going to the shop for both exhaust and cylinder head gaskets. Pictures to follow this evening.

[yammiemark]

It is what I thought after the weak peeing coming observed while the outboard ran. I broke two bolts removing the cover. I've already have one drilled and tapped. Tomorrow, I'll finish up drilling and tapping the second bolt and then tackle removing the cylinder head and cover. Then, clean it every thing up like I've already done with the exhaust water jackets, inner, and outer cover.

[DennisG01]

You may already have a system down pat to clean things, but... here's a couple easily obtainable chemicals that will allow you to soak parts in... all available at HD. Use the closest size "tub" to the parts you are soaking. I ended up using a plastic drawer from one of those cheap storage systems.

-- They sell 30% "cleaning" vinegar. Works great at dissolving salt buildup. It is VERY strong to the nose, though!
-- Another one that works very well is phosphoric acid. In HD's paint isle is "Concrete & Metal prep"
-- Muriatic acid works extremely well (it's HCl), but I'm not totally convinced that soaking for long times wouldn't eat into the aluminum a little. I've only used it for short durations and it was fine for that, though.
-- Still another great chemical is Rydlyme. That uses HCl, but in a small enough concentration to be safe for the aluminum. The muriatic acid is a higher concentration - and I suppose I could have just cut it down with water.
-- Small, brass or plastic detail brushes are good to have (the stiffer the bristles, the better).


Still wondering about the stream before and after impeller replacement, though???

[yammiemark]

I'll let you know, I cleaned inner cover in vinegar with a scrub brush. Pump is pretty simple.But, won't hurt to take off the gear case and look again.
~mark

[DennisG01]

I think you missed understood what I was asking. I was following up on the question I asked eariler regarding what the sttream was like before you did the impeller change as compared to the stream that caused you to post your question.