User Profile

[ZUL8TR]

Stock port timing on the Y80 is 62 intake and 83 exhaust Degrees BDC measured from bottom dead center from open to close. The exhaust is open a total of 83 x 2 = 166 crank degrees from open to close. The 88 Timing stamp I think references increased exhaust port open to close of 5 x 2 = 10 degrees more...

[ZUL8TR]

For the stock Y80 that diameter is about right and maybe just a bit too small but pitch will better zero it in as well as other things on the prop like blade shape, cup, rake, blade thinness, etc.

[ZUL8TR]

It might run without the stock Megaphone? But power would be down. Try to get the stock Megaphone complete and the 3 tapered seat Philips head bolts. The shims can be easily made from aluminum cans. There are 2 parts: per the parts manual the exhaust megaphone holder #6 and the exhaust megaphone #7....

[ZUL8TR]

If you want to pulse pump it with remote tank there is a hook up available at BTM, This will give you more water time with more fuel on board. The gravity tank is about 15 min at full bore, but plan on 10 to get back to the launch.

https://btmco.com/product/3250-yamato-fuel-pump-asse...

[ZUL8TR]

The other side of the prop has Hopkins is that different than McKean or was it reworked and stamped?

[ZUL8TR]

So all you did was glaze bust the cylinders with X hatch and the same pistons went into the same cylinder and the clearance is what it was + a smidgeon more due to glaze bust. Did you use a ball hone for the glaze bust?

[ZUL8TR]

The spark plug 18 x 14 mm adapters - call Tom Cronk he may still have some left. They are also available at local auto stores. If you need details on trimming the adapter to correct length and other details to fit the 14mm x 3/4 reach NGK plugs let me know.

You said - "I don't believe...

[ZUL8TR]

Where did you get that spec, top about 0.003" and bottom about 0.002"?

[ZUL8TR]

First loosen the prop nut. Push the pin from the longer protruding piece. It should move out with a drift and a hammer with support of the prop shaft on the pin mushroom side to prevent excessive lateral force on the prop shaft. If that proves a no go use the Clamp approach to get the pin moving. Once...

[ZUL8TR]

Tell us what you did on the rebuild? Did you bore out the cylinders, new pistons and rings or just rings, ring end gaps, piston to cylinder wall clearance, replaced rod and/or crank bearings, etc?

[ZUL8TR]

Well at least it reads correct on the 25ss merc with CD ignition with red TT lead wrapped on one plug wire the wrapped separate to the next plug wire in series. TT sold me the wrong unit their site descriptions and explanation back then was poor as well as their advice.

[ZUL8TR]

Doug That is interesting on the 2C since in catalog it is for 1 spark fire each crank rev. And the 1C is for 1 spark fire each 180 crank rev which a 2 cylinder 2 cycle does. When I ordered mine the tech guy at TT said that for my 2 cylinder 2 cycle outboard to use the 1C. Install per instructions did...

[ZUL8TR]

Luc
The Y80 is rated to 8000 but I would prefer to stay away from that limit. The mod guys go beyond that but I have been told they mod the top crank caged ball bearing that was designed to be loose so some oil could migrate there into a blind end. This is a shortfall of the Y80, 102, 302 design....

[ZUL8TR]

I have a tiny tach model TT226R-1C and it will not work well on the Y80, due to the not clean magnetic signal the TT locks up at high rpm. It is an older model bought in 2007. It works great on the CD ignition Merc 25ss.

Deeougee and Herb what model TT are you using and what are connection...

[ZUL8TR]

Luc
On that plug what is the number and reach length. Is the reach such that no plug threads protrude into the combustion chamber? Should not. My HS jet is set 26 clicks open, 28 clicks is one turn open.

Is your surprise that rpm is to low for the speed or the speed too low for...

[ZUL8TR]

Looking good!

Do you have a locked mag plate? Where do you have the high speed jet set? For reference my Y80 on the hydro 0.220" timing high speed jet on my carb at 26 clicks open - 28 clicks is 1 full turn open from dead closed. Running NGK B10EGV (#5927) plugs and 16:1 oil fuel ratio...

[ZUL8TR]

Inductive tachs have a tough time on the Y80 and 102 due to dirty not clean signal of the magnetic field around the spark plug wire and interference from the other wire. Good luck getting a clean reading, let us know what you find that works and isn't 4 Benjamins?...