No water for a Yamaha 1999 long shaft 2 stroke 8hp outboard motor

[Plymouth Sailor]

Any help appreciated on this: I replaced my impeller and thermostat this year. My motor turns off after approximately 3 mins I believe due to overheating. I don't see any water coming out of the "pee hole". I opened the plate on the thermostat and ran the motor and no water came through, any suggestions?

Thanks,
Mark

 

[DayDreamer41]

The water intake vent in the bottom of the drive is likely plugged with vegetation or sealife

 

[Plymouth Sailor]

Possibly, thought I checked that however maybe deep inside...

 

[DayDreamer41]

http://yamahamc.partsandwarranty.com/SyndicateNav.cfm?NodeID=1488072&Page=1

This site has some great exploded views

 

[Captain Ron 18]

Not sure, but would it make any difference if the impeller or thermostat were in backwards?

 

[JerryA]

I had an early 2000's 8hp Yamaha that wouldn't pee. A spider was living in the hole. Took a small screwdriver to clean it out. Also, as I remember, there was a short piece of hose that the water pump slipped into when putting the lower end back on. Maybe this fell off without you noticing. Just a thought.

JerryA

 

[Plymouth Sailor]

Thanks, however I believe both are correct. The impeller had a notch in it in which to place the key which I believe is in the right place. The thermostat was just replaced however no water is going to it.

 

[Plymouth Sailor]

Thanks, possibility that the metal pipe that draws from the water is out of place however I did guide it in.

 

[Brian D]

Like other, I had the same issue. So to check, I back flushed and it cleared the obstruction. To back flush, remove the hose from the pee hole and attach your hose to it. You'll need some additional piping and reducers to accomplish this task. Turn on the hose but do not get the water pressure too high. If there is an obstruction it should dislodge itself.

Now something to be aware of. And this is a problem I also had. The cooling system had a build up of calcium and salt (my motor was in salt water). You may have to take the block off and clean out the water paths.

 

[Chief RA]

I 2nd the pipe not aligned and out of hole in impeller housing. Chief

 

[Donnybrook]

Did you have water before you changed the impeller, or was that the reason?

 

[Tony_Furst]

Have you tried bench running the motor with earmuffs over the water intake openings and connected to a garden hose. This method forces water through the cooling system and can help flush debris from the passages.

 

[Plymouth Sailor]

yes, I've used the earmuffs, I've replaced the impeller, removed the plate on the thermostat, no water coming through, bought this motor used two years ago and it barely "pee'd" the first time I used it, last year I used it on a 5 mile journey and it worked well however never pee'd, this year it stalls after approximately 3 minutes most likely due to over heating. I need to buy a brand new motor but with a daughter in college and $3500 a pop, not going to happen this year. I guess I'll be using my boat as a barge this year and get a tow to the boat ramp at the end of the year! Thanks to everyone who responded! Best,
Mark

 

[LakeShark]

Common issue on merc is for the key to fall out when reinstalling the impeller housing and getting it all back togather. It's happened to me a few times where the shaft spun but the impeller stayed still causing no water. If you verify the tube is clear with compressed air or water as mentioned above it might be the next thing to try. If the key is missing it's usually laying in the lower cup on the impeller intake.

One other thought, did you remove and account for all broken fins from the old impeller when you removed it? If not one of them could be blocking the intake as well.

 

[Brian D]

One thing that is good to have is a high resolution image of how the cooling water flows in the 9.9. Here you go...

 

[isaksp00]

Since you are in Plymouth I assume this motor is and was used in salt water. Since it never had much cooling flow even before, could very well be salt buildup in the various passages in the block. There may be some sort of treatment you could use to loosen that up - maybe check in one of the specialist outboard forums, like iboats.

 

[Chief RA]

The calcium removal solution sold in supermarkets will work if you put it in a squeeze bottle and push it backwards into the pee hole. Keep doing this and let it sit overnight, then back flush with water hose. If you put it back together lying on its side, you can expect that the tube is NOT in the hole as it drops out before foot seats, It must be upright! If all else fails, get an estimate of repair and get it fixed. Chief

 

[2taylorscotts]

My Yamaha 9.9 had the same issues, did just about everything mentioned, and traced the water flow step by step. Before getting drastic I disconnected both in and out lines from the cooling jacket, put a piece of hose on one end, took a deep breathe and blew----got a hand full of snot that was a spider and eggs in a previous life. Problem solved! Had already replaced the thermostat, impellers, seals and gaskets ( in my slip, tied to the stern in an inflatable dinghy-- I don't recommend it!)
Best of luck

 

[isaksp00]

On my Honda 8, it is tricky to push the lower leg back up and keep the lower part of the water feed tune aligned with its upper tube mate, even if vertical. Plus you can't see it to verify after you push it up. Just might be your culprit, though the historically slow flow seems to indicate some sort of blockage as well.

 

[kloudie1]

This Yam 9.9 had sat idle for a few years.. you can see we had to open the cylinder head to get at the deposits.. The exhaust ports on the right side have cooling passages next to 'em. You can see they were about fully plugged..
Yes, it was a bugger to get the water pipe and stuff all lined up..