Association Forum - Yamaha 9.9

Assn Members Area · Join

Home.

Association Forum

Ships Store

Cruising

Racing

Technical Tips

Photo Gallery - New

Boat Search - Updated

Manuals & Brochures

Swap Meet

Links

Officer Flag Line & Staff

Bylaws & Constitution

Members Area

Join the Association

Notice:
The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.

Association Forum

Username:	Password:
Save Password
Forgot your Password?

All Forums

Catalina/Capri 25/250 Sailor's Forums

Catalina 25 Specific Forum

Yamaha 9.9

New Topic

Topic Locked

Printer Friendly

Author

Topic

JPS109
Deckhand

Member Avatar

20 Posts

Initially Posted - 08/13/2010 : 11:19:55

My 1991 Yamaha 9.9 overheated after presumably coming in contact with a submerged plastic bag. After a while, I was able to free the flywheel and then start it the next day. It now starts OK, but with a lot of smoke. I've only run it for 20 seconds or so for fear of doing more damage. The smoke has lessened, but I don't want to push my luck. Am I looking at a blown seal, valve, piston, or 'only' a water pump?

Jim
'87 Catalina 25 #5574
Blown Away
Monmouth Beach, NJ

Edited by - on

mytime25
1st Mate

Members Avatar

USA
50 Posts

Response Posted - 08/13/2010 : 14:56:47

Jim,
Is your motor a 2 or 4 stroke? Did you notice if the cooling water stream was flowing steady? If it isn't check pump / impeller
That's all I can come up with Good Luck

Edited by - on

Leon Sisson
Master Marine Consultant

Members Avatar

USA
1893 Posts

Response Posted - 08/13/2010 : 19:22:20

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by JPS109
 My 1991 Yamaha 9.9 overheated... After a while, I was able to free the flywheel... It now starts OK, but with a lot of smoke... Am I looking at a blown seal, valve, piston, or 'only' a water pump?<hr height="1" noshade id="quote"></blockquote id="quote">What model is it? If it's a 4-stroke, then the excessive smoke probably means it's toast. (Well, any time overheating locks up a motor, you're probably screwed.) But motors are expensive, so don't jump to conclusions. I'd try a compression check, and see of you can get a look at the cylinder walls without removing the head. Also, listen carefully for new knocking noises while it's running at low speed.

If no tell-tale water stream, then may need at least an impeller. I seem to recall those water pumps being marginal on a good day. Without being sure it's pumping water, you might still be able to run it very briefly for troubleshooting purposes only. Don't run it above idle, or for more than about 30 seconds at a time before letting it thoroughly cool.

On the Yamaha 4-stroke 9.9, I think you can double check for water circulation by removing the thermostat, pouring some water in there to fill the passages, and leaving its housing open while very briefly running the motor. If idling the motor doesn't immediately push water back out the thermostat housing, then suspect a bad pump.

Let's hear some other opinions and troubleshooting suggestions before giving it last rites.

-- Leon Sisson

Edited by - Leon Sisson on 08/13/2010 19:34:30

Jmurfy
Navigator

Members Avatar

USA
176 Posts

Response Posted - 08/13/2010 : 20:46:04

I have a 1998 Yamaha 4 stroke which I've owned for 5 years. It never had much of a stream until this year after I changed the impeller. What color is the smoke? I hate to give bad news but I'd say you have a big problem.

Edited by - on

Ed Cassidy
Captain

Members Avatar

USA
365 Posts

Response Posted - 08/14/2010 : 11:37:54

The reality is that if the motor locked up, it was because metal expanded to the point that it couldn't slide on other metal (piston and cylinder, camshaft and bearing, piston rod and crankshaft) In this case, it is most likely piston to cylinder wall. The instant that happens, there is damage done. If a two stroke and if there is water flow, start it up and let it run. You won't cause any additional damage that wouldn't be corrected with boring and an oversize piston. At least you would have an idea if it were still usable for the rest of the season as it is. But if it locked up, it will most likely need to be gone through. There is a very slight chance that the piston to cylinder wall damage is so light that it would be OK to continue using it but that would be unlikely. Sorry.

Edited by - on

JPS109
Deckhand

Members Avatar

20 Posts

Response Posted - 08/16/2010 : 06:34:11

All,
Thanks for your advice. Wound up being not too serious. Compression was good, cleaned out the impeller, changed the thermostat and all seems OK.

Edited by - on

OJ
Master Marine Consultant

Members Avatar

USA
4382 Posts

Response Posted - 08/16/2010 : 06:43:35

Yeah, sounds like you just honed the cylinders a bit . . .

Thanks for sharing this information - I would have never thought a plastic bag could cause such a problem.

Edited by - on

Topic

New Topic

Topic Locked

Printer Friendly

Jump To:

Association Forum

Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.