Yamato 80 ???

[flybynight55]

I have a Yamato 80 that i got with a boat purchase. Its really clean and looks new to me. I have no idea how much if any use it has had. Can anyone tell me anything such as horse power, size or type boat it is best suited for? Also, what type oil and gas does it use and what ratio??? Are the 80"s current race engines?? I am new at this..Thanks

[Tomtall]

flybynight

Most of the technical information you seek can be found at this link on the 80 motor. It is from the RPM marine web site.

http://www.yamatoracing.com/y80manual.pdf

This engine is still raced in APBA,NBRA classes that can be found at those
web sites. One of the more popular APBA classes for this engine is the 20SSH class.

[ZUL8TR]

Y80

I have a Yamato 80 that i got with a boat purchase. Its really clean and looks new to me. I have no idea how much if any use it has had. Can anyone tell me anything such as horse power, size or type boat it is best suited for? Also, what type oil and gas does it use and what ratio??? Are the 80"s current race engines?? I am new at this..Thanks

The engine manual in the link is good info. As far as fuel try to get non ethanol the E10 stuff is bad for these engines, power loss and it damages some components. The manual has 25:1 fuel oil ratio, I use 20:1 with non ethanol.

Try to run the engine first for 15 + minutes. There is no water pump in these engines they cool by prop spray forced cooling into the 2 small holes at the bottom of the exhaust snoot on the port side. You can start without a prop on a stand and a garden hose. Just duct tape over the 2 holes and remove the brass plug up on the exhaust tower and place a small rubber hose in there to protect threads then attach to your garden hose to the rubber hose (be inventive here I use a brass jet attachment to hose from Home Depot.

Redart the timing by pushing the mag handle to the left facing the engine unless sombody has locked the mag? When running adjust the low speed jet for idle, the high speed jet in the front of carb should be initially set about 7/8turn from closed seated position, the manual is wrong here it states 1-1/2 turns open. To find closed position of adjustable jets gently turn CW till very gently seated, DO NOT FORCE it will damage the needle tip with a groove.

To check ring and cylindere condition do a cold compression check with a good gage, Spray correct mix oil and gas into cylinderes to lube the walls via several rope pulles before the compression test and keep the spark plug wires way far away from the open plug holes. A good condition Y80 should give about 150 psi in both cylinderes after about 4 rope pulls. There should not be much difference between cylinderes. If readings are lower you can check for ring and cylindere wear by squirting in straight outboard oil pull several times to distribute then redo the compression. These higher numbers will reveal issues.

Post your results

There is lots of info on this site just ask.