What diesel engine is this on my new-to-me 1978 Catalina 30

kloudie1 · May 4, 2023

Welcome to the forum!
Not 100% on this one but I think it’s a Yanmar YSB 8 or YSB 12.
The hand crank chain might say it is a YSE-8?
This chart is taken from Toad Marine's web site:

Y Series
These horizontal models lay down in a low profile. The series was updated three times with the YSE being the earliest model, followed by the YSB and then the YSM. Either a 2:1 or 3:1 transmission. The models were sea-water cooled, singe cylinder, heavy duty. This series includes the following engines:

Engine	HP	Years In Production	Comments
YSB12	12	1976 - 1977	B=Between
YSB8	8	1976 - 1977	B=Between
YSE12	12	1974 - 1976	E=Early
YSE8	8	1974 - 1976	E=Early
YSM12	12	1977 - 1980	M=Modern
YSM8	8	1977 - 1980	M=Modern

Tally Ho · May 4, 2023

Maybe we can play a game of what it isn’t. …

Not a Yanmar 2GM20F.

Greg

jssailem · May 4, 2023

Catalina data base on the data sites like SailboatData.Com say the auxiliary used was “variable.”

Wiki shares this bit of info (sourced from Frank Butler)

“The design was initially fitted with a Japanese Yanmar diesel engine or a Universal 5411 or Universal Atomic 4gasoline engine, but by the mid-1980s these had been replaced by the three-cylinder Universal M-25diesel.[1]”

Your best bet is to inspect your engine and identify the serial # and any labels inscribed on the engine.

What diesel engine is this on my new-to-me 1978 Catalina 30

Bob Fiske

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SBO Weather and Forecasting Forum Jim & John

Bob Fiske

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