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1995 Yamaha T99EXHT impeller replacement seal housing removal

westcoastdonni

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"1995 Yamaha 9.9HP High Thrust

"1995 Yamaha 9.9HP High Thrust Long Shaft Outboard

Well its summer but the snowball keeps rolling around here. What started off as an impeller replacement has turned into a complete nightmare.

I started off by struggling to no end to get the gear case off and finally found the solution by heating the 4 bolts that hold the gear case and knocking out the corrosion enough for the lower unit to come free.

With the lower leg free, I then removed the four bolts holding the top of the water pump on and that came free without to much trouble. Of course the impeller was fine so I popped on a new gasket and tightened up the four bolts. Only on the last one did I tighten it just a little to much and I felt it weaken and snap.

So I drilled a hole in the bolt and tried to use a broken bolt extractor to remove it. Of course that broke in the broken bolt.

Thinking I may be able to get at the bolt if I remove the seal housing below the water pump, I began prying off the seal housing (as stated in the clymer manual)and it actually separated.

Now I have the seal housing free but the drive shaft is stopping it from sliding off.

So my question is, do I have to remove the drive shaft to get the seal housing off or is there another approach with the seals in the housing - my clymer manual doesnt say? If it turns out that the drive shaft has to be removed wich looks complicated and requires special tools, is this something I want to do or should I just lower my head in shame and take it to a dealer?

Thanks in advance for any help."
 
"Take it to a dealer, let them

"Take it to a dealer, let them salvage your boating season and in future change (or at least pull and inspect) the impeller every second year - adding a good dose of anti-seize to the bolts on the lower unit..."
 
"Thanks for the suggestion Gra

"Thanks for the suggestion Graham, I took it to a dealer and after explaining my above situation the service guy told me it was a "major" repair. He stressed that several times. They said they would have to initially send it out to have the bolt/extractor dissolved with acid and then go at the prop shaft, carrier, pinnion, driveshaft, seal housing $$$ They also warned that because the motor was 12 years old that most likely it would be tough to work with due to parts/bolts seized/breaking.

They must have seen the horror on my face because one of the guys said I could try and use some sealer and just bolt the seal housing and pump down with the three bolts.

I liked the sound of that and grabbed a tube of Yamabond Semi-Drying Liquid Gasket , a couple water pump gaskets and a litre of gear oil.

Luckily, my sheet metal buddy was a couple blocks away so I stopped in to see if he had a suggestion to get at that broken bolt with broken extractor (bbwbe) stuck in the housing. He said he had a neat trick to remove the bbwbe.

He grabbed his "plasma cutter" and said he would use it to atomize the broken bolt extractor. Sure enough two super quick hits and the broken extractor virtually disappeared with no damage to the housing. It barely even hit the broken bolt.

Now it was just a case of drill/tap the broken bolt, painting on a new gasket between the seal housing and putting everything back together.

I ran it 8 hours today trolling for Salmon off Sooke and she ran like a dream. 6 fish for the smoker and I couldn't be happier.

If in doubt blast it out ; ^ )"
 
"Brett, can count on an hours

"Brett, can count on an hours labour and the cost of parts. Most dealers would be looking for something in the 150-200 dollar range (at least where I am).

This is a fairly simple job, particularly on a little 9.9 and you could pick up an aftermarket kit for somewhere around 30 bucks...."
 
"Hello

I was hoping that so


"Hello

I was hoping that someone could help me out.
I am having a problem with my 1988 Yamaha 8HP. I can't get the lower unit to drop out. It falls down about an 1/8" but that's it. I removed 4 bolts as well as the gear shift mechanism (basically pulled out the rod that lifts the gears and connects to the gear switch) and I left it in neutral. I've never worked on a boat engine before or any engine for that matter so I'm not sure what you mean when you say tower housing.

The reason why I am taking off the lower unit is because my engine keeps seizing up. It worked perfect for a couple of months and then 1 painted it one day. A few days later I went to run it and I heard a little squeak as it started up (only briefly though). IT appear to run fine. The next time I tried starting it up (maybe a week later), I couldn't budge the rip chord. Something was seized. I removed the plugs and cranked on the fly wheel with my socket wrench very hard and I managed to get the fly wheel to turn. IT was was very hard at first but then got easier. I was now able to start the engine up with the rip chord. IT started up on maybe a 1/2 pull (the engine is awesome) and it ran ok. It sounded like it wanted to stall at low idle though. one week later, it was completely seized again and I went through the same steps above. This happened 4 times in a row now. I talked to a lot of people and some people say water much be getting into the cylinder and rusting. I tried looking into the plug hold and I might have seen I a little rust but I'm not sure what to look for. Another person told me that the gears or components below the powerhead are probably rusted and keep seizing, which is why I am trying to remove the lower unit. The gear oil seemed fine and I changed it. However, some hard lube-like substance along with some fine particles (metal flakes, paint or sand) seeped out of the that 1/8 opened I made (just a tiny amount came out). Anywho, I really want to get this fixed and there doesn't seem to be any boat mechanic around here that wants to help me (I called 3). If anyone has any idea on what might be the issue, Please let me know. Oh, I should mentioned that there is a seal between the bottom of the powerhead and engine cover and the seal seems to be large and it's definitely not sealing anything. Maybe water got into the gears through there.

any thoughts? I have a million pictues if interested.

thank you much in advance,
Rich"
 
Heat the bolts as hot as you c

Heat the bolts as hot as you can get them with a probane torch and tap the side of the leg beside the bolt or thread the nut back on and tap it gently. It takes a while but you will find the corrosion will fall out and the leg will free up from the housing.

Perhaps the drive shaft is stuck in the power head and that is stopping you from pulling the leg off.

The shift shaft is separated right. When you move the gear lever from neatral to forward you can see that it is apart right.

Good luck.
 
"Thnk you very much for respon

"Thnk you very much for responding and your help. When you say torch the bolts, are you referring to the 4 bolts that bolt the lower in place? They come out very easy. Is heating still necessary?
I think I have the gear lever apart. I pulled the rod out that connects to the shifter and the the mecanism that twists to change gears. Are you saying that I have to some howw get in there and disconnect the little components? I took a some pictures, I can upload them and show you what I mean if you are interested.

thanks again

Thanks again"
 
Perhaps your leg is mounted di

Perhaps your leg is mounted differently then the 9.9. Im not familiar with your motor.

Is it mounted with nuts on studs or by bolted in. I assumed it was nuts on studs like my 9.9.

It may be a good idea to start a thread for your 8 if it sounds different.

Can you purchase or borrow a Clymer manua. Mine is for 9.9 1986-1999. But I just assumed they would be similiar in design to your 8.
 
"Hi Michael,
It's bolted


"Hi Michael,
It's bolted on (no nuts). I finally got it off at about 1:45AM last. I had to put a block on the lower fins and "tapped" it off, she evenually worked her way off but it was sticky until the point that it came off completely. When I pull the rip chord with the lower unit there is a profound squeak coming from some where. I think what ever caused the engine to "sieze" is still rusted and dirty. I couldn't tell if it was a linkage or within the cylinder. I put the spark plugs back on and checked to see if the squeak noise muffled and it didn't. I think that's the good noise because it makes me think it's a gear or linkage just below the powerhead (not in the cylinder). I tilted the motor back and sprayed a lot of WD40 in there to see if I could change the tone of the sqeak but nothing. Any thoughts on what it could be?
I am getting a manual in two weeks (I'm leaving for China tomorrow). When I get the manual, I think my next step is to try to remove the powerhead to see what's below (unless you have another idea).

Thanks again and sorry about the long thread. i tried starting my own but couldn't for some reason.

Rich"
 
I have a 8 horse Yamaha long s

I have a 8 horse Yamaha long shaft that does not spit any water out of the coolant return. Is replacing the impeller an easy task or is it rather invasive? Can anyone tell me the best action to take?
 
Well I started with a new impe

Well I started with a new impeller and my water circulation improved a bit. But when I took out the three water lines that come out of the engine block I noticed the top spout was only dripping.

I reconnected the lines and tried to run it for a while but it started over heating and started to really smoke bad although a good stream of water was coming out

I was convinced that I had some major problems so I tore off the cylinder head and noticed every thing was intact but the head gasket was really full of salt deposits and some of the passages in the cylinder head blocked completely. I scraped off all the salt and blew out all the water passages with compressed air. I cant beleive how much salt and other debris came out.

I slapped it all together and now I have water circulating properly out all the water ports and no overheating.

So if I had to diagnose a water circulation issue with an outboard I would:

Pull off the water lines and see if water is passing through all of them. If water is coming out normally you may have some debris in the water outlet that passes outside the motor. A toothpick pushed from the outside pushes out whatever may be blocking it.

no flow or weak flow!

Pull off the leg and inspect the impeller. Replace if necessary.

If the impeller seems intact. You may want to pull off the cylinder head and clean all the water passages and replace the head gasket.

If your motor spent much time in the salt chuck and was not flushed frequently it is most likely really clogged with salt like mine was.
 
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