50hp 2 stroke...overheated for 2 minutes...any permanent damage?

[boat_mike123]

Hello. I am new to boating..I just got my old 2001 yamaha outboard 6 months ago, taken it out , works great.

When I came home this time, I put on the eat muffs to clean out the saltwater, and run the motor. Well I guess when I turned the water on full blast, the ear muffs popped off, and like a dummy I didn't notice. Started the engine and in about 1 minute the over heat alarm went off and smoke was coming out of the tell tale. I turned it off immediately. Area where the coils and plugs are was very hot, as well as the head.

I waited 1 hour and redid the process, and made sure the earmuffs were on this time. EVerything ran smooth. Telltale was spitting out luke warm water, no alarm, and after 5 minutes the engine was only cool to the touch.

Of course me being paranoid, I wanted to ask you guys if I permanently damaged my motor. Is there anything I should check? I checked all the parts like thermostate, lines, all seemed good, no burns on any wires. And like I said, the tell tale was spitting plenty of water the second time around.

I guess my question is, is there any permanent damage to my new, awesome motor that I love? I would hate to find out I bricked it.

[panasonic]

I wouldn't worry too much about the engine itself...it didn't sieze up did it?

You probably roasted the water pump. I would definitely drop the lower unit and inspect the impeller and cup. If you need to replace it buy the proper Yamaha pump kit...they are better than the aftermarket ones.

[DennisG01]

I agree. I highly doubt you did anything to the actual motor. About the only thing that may have happened would be damaging the impeller. It "might" be fine, but you probably won't know until you run it on the water... and then, if it happens to be slightly damaged, you might end up making things worse when a vane breaks off.

On the other hand, if you don't know when the impeller was changed last - and I'm going to assume you may not even know what it is since otherwise you probably would've asked about whether you cooked it - now is a perfect time to put a new one in. It's a maintenance item, anyways.

Overall, don't worry - you didn't do any permanent damage.

[boat_mike123]

I actually just had the impeller done when I bought the boat. Yamaha brand part and installed at a dealership. Now that I watch some youtube videos it doesnt seem to complicated to at least remove the lower unit to inspect the impeller or even replace. I will check that before taking it back out.

Thanks for the input guys.

edit: The motor did not seize up or anything. RPMs on the motor sometimes jump for a couple seconds then chills back out but it always has seemed to do that.

[boat_mike123]

Quick question, if the water is spitting generously on the muffs now, would that mean the impeller is good? or is that just the water pressure forcing it through? The tell tale is a nice good stream.

I'd rather not try to take off the lower unit housing but if you guys think I should I will.

Impeller probably had 2 hours on it prior to this.

[TownsendsFJR1300]

Quick question, if the water is spitting generously on the muffs now, would that mean the impeller is good? or is that just the water pressure forcing it through? The tell tale is a nice good stream.

I'd rather not try to take off the lower unit housing but if you guys think I should I will.

Impeller probably had 2 hours on it prior to this.

That overheat with NO WATER put MANY years of wear and tear on it... MANY...

As noted above, should a vane break off (usual in older engines with old impellers) and get lodged in the cooling system, you'll have a
whole lot more tear down/repair to fix that NEW issue..

Change it, the SS cup with genuine parts..

[boat_mike123]

That overheat with NO WATER put MANY years of wear and tear on it... MANY...

As noted above, should a vane break off (usual in older engines with old impellers) and get lodged in the cooling system, you'll have a
whole lot more tear down/repair to fix that NEW issue..

Change it, the SS cup with genuine parts..

Thanks guys. As you all suspected, I took apart the lower unit and even though its a brand new impeller, it was super deformed and even missing a small part piece of one of the blades on the impeller. Thank god for youtube as I don't want to pay $250 again for such a simple task!

I ordered the new impeller. Everything else seems fine, like the rubber seal and guide seal, all that.

Should I buy anything else? Housing and the seat area looked fine no warping or discoloration.

What is the SS cup?

[boat_mike123]

I ordered the whole kit here, just in case, but I think just the impeller is bad...

1 x Yamaha New OEM WATER PUMP & IMPELLER REPAIR KIT 63D-W0078-01-00

[TownsendsFJR1300]

Thanks guys. As you all suspected, I took apart the lower unit and even though its a brand new impeller, it was super deformed and even missing a small part piece of one of the blades on the impeller. Thank god for youtube as I don't want to pay $250 again for such a simple task!

I ordered the new impeller. Everything else seems fine, like the rubber seal and guide seal, all that.

Should I buy anything else? Housing and the seat area looked fine no warping or discoloration.

What is the SS cup?

It's the cup (part #22) the impeller rides inside. ("insert cartridge" per parts diagram). That IS INCLUDED in the kit you ordered along with seals, etc


Usually if that gets super hot, it'll warp the housing (part #21) which is not included . Inspect that closely. If any doubt, replace it..


We're you able to find the missing impeller part?




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