Replacing an A4 with Yanmar 8HP Diesel

[Muscongus]

I have a '77 Cat 27 that came with a noon functioning A4. It had pulled in some sea eater and was left to sit for a few years.

So, I purchased a gently rebuilt Yanmar single cylinder 8HP motor, transmission, fuel system, prop, shaft, wiring harness - everything. (from a boat that was being parted out)

I'm wondering about things like shaft angle, sound proofing, if the opening to the sail locker should be closed up, that kind of thing. Really, if there's is advice, I'd like to hear it.

thanks,

Dan

 

[py26129]

Dan

As far as shaft angle is concerned, you should be able to find the maximum angle that the engine can be inclined in the shop manual. If it's a YSE8, I have a manual I can share, if you don't already have one.

In principle you should positionthe engine in such a way as to keep the shaft angle the same as it was with the A4.

Things like sound proofing etc. will become apparent. However, if you have a chance to install some upgraded sound proofing, I would do it. The Yanmar will not be nearly as smooth as the A4 and will probably be alittle louder.

We had a YSE6 in our Paceship 26 and it was a great little engine. Reliable as a stone.

Matt

 

[jrowan]

I used to have a YSM8 on my last boat, an S 2 28 footer.
So although the Yanmar is only 8 horses at full throttle, I know
that it can push the C 27 along at hull speed in mild wind & waves.
Expect to run at about 3.5 to 4.0 knots max in steeper chop waves.

The Y series engines are extremely tough & reliable. The A 4 engine in a C 27
is way overkill in size & horse power. But do keep in mind that the Yanmar 1 cylinder engines are rather noisy & they vibrate a lot. I've heard other sailors
joke that these Yanmars can shake your filling loose! But that's the only downside.

I would make sure you buy new motor mount brackets, so that the rubber base dampeners aren't too hardened up from age. Our boat didn't even have any rubber at the engine brackets, so hence the vibration. Sound deadening can be helped, but not eliminated. I would replace the fuel tank, fuel supply lines, & fuel filter canister / housing, as any gasoline contamination can have dire results to a diesel engine.

I also have a copy of the YSM8 Engine repair manual if you need it.
Send me a request via my page on this site if you want a copy.
Good luck & enjoy the reliability & great fuel economy of this 1 banger engine.

 

[CalebD]

I'd get a working A4 before I'd go for a 1 lunger.

 

[Muscongus]

Thanks everyone,

I've got a copy of the manual for the yanmar. It's an SVE8 (as I recall, any way).

There are no engine mounts with it. In the Boat it came out of, it was just lag bolted to the mounting area in the engine compartment.

I'd like a little bit larger motor, but, the price was right and I've already got the yanmar. Plus it was rebuilt 100 hours ago.

On my Bristol, we went out in some heavy winds and, in a gut, could not turn the boat. That is a b24 and has a Honda 9.9 4 stroke. It weighs about the same a the C27, so, I've got to wonder about those situations with the yanmar. of course, those times are not that frequent, so, likely not a big deal for coastal cruising.