500ccR Yamato Test

500cc Yamato in 500 Runabout at Oroville Kilos 2013. Stuck the engine at well over 100 MPH without pulling the pipes!

[@goropeza101]

Not many people in my speedboat crowd knows what a Yamato outboard is but for those that race tiny hydros the Yamato rules!

[@dmanindfw]

My Uncle used to be one of only a handful of importers of these fine little engines. They hold several kilo world records running Yamatos.

[@anycolouryoulike75]

I love the way a surface prop works

[@mckeanbrosoffroad150]

I witnessed a Yamato 500cc do 175 hp on a dyno after extensive tuning and port polishing. They were monsters.

[@Chadwicky69]

Bad Azz!!!!!!! I have a vid of me blowin up my modded 6cyl Evinrude thats very similar.....the only thing you forgot at the end is "And thats how you blow a motor up!"

[@BuckingFastard]

+Chad Schram seen it many times and also seen the boat on S&F

[@freeradical431]

you need Dumonde Tech Racing Oil, best Ive ever used!

[@gabrielerossi8398]

if you use it with half pipes it is normal for it to break

[@shaveyh10]

Cha-ching.... Been there, done that, but with Koenigs

[@brianseifer9744]

KOENIG, the master Race, Yamato ok, I did a C class stock 24.1 cu.in , sure made the little A stock peanut boat jump out out of water ,2 sec. on plane, didn't get 70 only 67 mph , like the runabout side cam was 1st class . In early 80' S lot more alky Yamato around.

[@andykerr3803]

Is it a four cylinder opposed? Reminds me of the Koenig.
I guess he seized or blew it... Crazy, the 6 cylinder Mercs would do almost 60 races without a tear down

[@bob.w3984]

Guess it seized. Used to play with seadoo jetski motors. It was easier. Make a run and watch the Tach. At wfo the peak rpm would drop a few rpm and you get out of it real quick and then tweak the carbs and retest.. jet pumps are like a Dyno. With a prop its a little more variables.

[@albychainsaw80]

Broker engine