91 Octane and small engines

[sumpnz]

I've gotten sober 91 octane that my chainsaw flat wouldn't run on.  Best as I can figure it was recreational fuel meant for snowmobiling in far north or something, so the vapor pressure was all wrong for summer time use in a 2-cycle.

Usually I get mid-grade (89 octane) as my equipment (riding mower especially) like it better than 87 but it's cheaper and just as good as 91.

[RoadKingLarry]

If it's not an OHV engine, yes. Even moreso than you may realize. Non-OHV small engines are a low-compression flathead with oil-slinger lubrication and magneto-driven ignition. Short of main bearing/bushing inserts rather than babbitt, they're operationally identical to a Model T engine (albeit minus 3 cylinders).

Brad

My 27' sailboat has a 4 cylinder flathead. It's probably closer to a mid '50s tractor engine than a Model-T.
I run ethanol free gas and add Marine Sta-bil, seafoam and Marvel Mystery Oil.
As far as I know it.is the original,  unmolested equipment.

[Brad Johnson]

My 27' sailboat has a 4 cylinder flathead. It's probably closer to a mid '50s tractor engine than a Model-T.
I run ethanol free gas and add Marine Sta-bil, seafoam and Marvel Mystery Oil.
As far as I know it.is the original,  unmolested equipment.

What mfg? IIRC, industrial & marine flathead engines were common even as late as the mid 80s. Dunno if they all came from one mfg or if a lot of folks were still making them as special-purpose units. My guess is that it was for their mechanical simplicity.

Brad

[Hawkmoon]

My 27' sailboat has a 4 cylinder flathead. It's probably closer to a mid '50s tractor engine than a Model-T.

Atomic 4?

[RoadKingLarry]

Atomic 4?

Yuppers!
Great little engine when even half a care is given to maintenance.

[Brad Johnson]

Atomic 4?

Yuppers!
Great little engine when even half a care is given to maintenance.

Cool engine. Never heard of them before. Not a bad production run, either (35 years, 1949-1984).

Brad

[RoadKingLarry]

There is a company that supports the A-4 called Moyer Marine. They are the go-to supplier of parts.
They recently began making new castings, block, head, manifolds, cranks, pistons... you can literally get a "brand new" 70ish year old engine.

[Hawkmoon]

Yuppers!
Great little engine when even half a care is given to maintenance.

Absolutely. It's a pity they're out of production, but I guess they were overrun by the little YanMar diesels

[RoadKingLarry]

Moyer Marine has sort of put them back in production, like I said above, you can buy a sort of brand new Atomic-4 today. All new castings, all new block, head and manifolds.

[Hawkmoon]

Moyer Marine has sort of put them back in production, like I said above, you can buy a sort of brand new Atomic-4 today. All new castings, all new block, head and manifolds.

Are they selling complete engines, or just a box o' parts?

[RoadKingLarry]

They'll sell you a complete engine.
Sailing acquaintance of mine did a rebuilt swap a few years ago in his '80s model Catalina 30. from what I saw the customer service was pretty darn good as well since the guy swapping engines is less than wonderful as a mechanic.

[castle key]

Just refilled my sober gas for small engines.

It's easy to get around here as there are so many boaters, but what a pain waiting for the Richmond visitors to fill up their boats. Buy it at the marina and bring even more money to my area!