15HP Yamaha Enduro

[onestepcsy37]

Good go hear some of the advice around here actually works! FWIW, after I unstuck my nissan I ran a tankful of gas/oil mix - maybe a quart - through it with extra oil in it, just to make sure everything that needed oil got plenty of it. Instead of 50 to 1 it was maybe 35 or 40 to 1.

[sy_gilana]

Originally Posted by Guy

I see the crankcase view but what do you see? How can you see the bearing journals? How can you see anything of importance without taking it all apart?

Well its running again. YAY!

Guy, to answer your particular question, if you can see a general cover of surface rust, its safe to assume that all components in there are equally affected as they get the same amount of oil. These are very good motors, and there are a few secrets, like not reversing the spacer rings that hold the needle roller bearings in at the gudgeon pin, they are actually designed to conduct heat away from the needles and transfer it to the piston. There is a significant amount of cooling furnished by charge air heading into those chambers in the photo.

To the OP in future if you are going to leave it here is what I do.

Flush in fresh water for 10 minutes, using a small amount of fuel at 25:1 oil ratio.

After 10 minutes, remove the fuel hose, and keep it running by opening the throttle wide open and simultaneously pulling the choke out, when its just about to die, push the choke back, as it revs up, choke it again, keep doing this until all the fuel in the carb is gone.

There will be serious smoke, and that is what you want.

Never let the fuel evaporate from the carb, you must use it up.

Store vertically, no matter what the manual says, keep it vertical.

Plug the exhaust with an oily rag, or cover the prop with a similar rag.

Do not be scared to rinse the motor often with fresh water under the cowl. When my dink is full of rainwater, I bail it onto the engine.

[sy_gilana]

Originally Posted by amytom

Attachment 88152

Just happen to have one apart in the garage...


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Hi, Amytom, That is a 63v motor not an Enduro, but its identical for the purpose of this thread. That is the motor I have, also called the "Leisure" model in the far east, or "Saltwater Series" elsewhere. This is a faster and more economical motor than the Enduro. The timing is very important to get right.

Why is it in the Garage?

Please stuff a rag in there to prevent moisture ingress.

[Tommee]

Thank you for advice for the next time, sounds good. You do mean run the engine flat out, obviously out of gear, when emptying the carb? I hate to hear it scream like that but guess its no worse than when actually in use.

[amytom]

Originally Posted by sy_gilana

Hi, Amytom, That is a 63v motor not an Enduro, but its identical for the purpose of this thread. That is the motor I have, also called the "Leisure" model in the far east, or "Saltwater Series" elsewhere. This is a faster and more economical motor than the Enduro. The timing is very important to get right.

Why is it in the Garage?

Please stuff a rag in there to prevent moisture ingress.

Carb and lower unit rebuild. The model/year tag is missing but I believe it's a '98 vintage and that's the parts I've been using.

It was given to me free with a "bad coil" turns out the spark plug boot was loose on the high voltage lead.
It's been running great for a couple of years but recently started leaking at the seals under the water pump and for high speed it ran a little better with partial choke. Getting that lower unit apart was definitely a test of my patience. Local shop screwed it up when they tried so I had to replace the whole upper bushing and seal housing too.

Will be test running it this week as I just got it back together.

If the carb acts up I'll be back here looking for advice.



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[sy_gilana]

Originally Posted by Tommee

Thank you for advice for the next time, sounds good. You do mean run the engine flat out, obviously out of gear, when emptying the carb? I hate to hear it scream like that but guess its no worse than when actually in use.

It wont go flat out..the throttle must be wide open, but the choke causes all that vacuum to suck huge amounts of fuel and oil in, and it does not all burn because of insufficient air, so it covers like a fog. It will not scream.

[amytom]

Well, tested out the rebuilt 15 with the new to us dinghy. Much better. Still runs rough at and just above idle but at WOT it screams at 20knots with 400lbs of passengers. The timing is probably the issue- idle at 5 an wot at 30btdc. Not sure what it should be or even how to adjust it.
Any thoughts?


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[a64pilot]

Originally Posted by onestepcsy37

Good go hear some of the advice around here actually works! FWIW, after I unstuck my nissan I ran a tankful of gas/oil mix - maybe a quart - through it with extra oil in it, just to make sure everything that needed oil got plenty of it. Instead of 50 to 1 it was maybe 35 or 40 to 1.

This is a good idea, I run one ounce per gl of gas normally,
One edit, three ounces per gl