where do some people get this information?
All diesels have governors.
that maintains it's rpm
regardless of load has what's called a variable speed governor.
Most engines, car AND MARINE
have limiting speed governors, they simply stop the engine
A big, old, 2 stroke
71 series or 53 series is only good for sitting in the back yard and making your neighbors angry. Unless you're using it in the back woods, stay away from them for boats. They're very heavy and don't put out much power.
More cylinders = smoother running, simple.
for boats, zf is the most common. Twindisk is experiencing a bit of a resurgence, but zf is the most common and about the same price
For 20-30 hp, zf 10m-15m or the older hbw 100- hbw 150.
Engine recommendations for budget
. ASSUMING A USED ENGINE:
, Kubota. I'd lean towards Kubota for rebuilding parts
I'm building a 49 foot Cat and we're marinizing vw tdi engines (without turbo, so technically SDI). 40 hp at 2600 rpm
, 60 hp at 3600 rpm, 450 lbs with tranny. We've rebuilt the engines to "new spec".
We're using the zf 25a transmission
, it's hydraulic whereas I'd recommend a mechanical tranny for ease of repair if you're watching your budget
long term. The zf 25a is the same price
as the zf 15m, due to it's popularity and availability, but it'll handle up to 150 hp as "light duty" or up to 60 hp as "commercial duty".
There you go. An older yanmar
or Kubota (even from a lawn mower) and if it doesn't have a transmission, zf marine
Be very careful buying
an engine and trying to get an SAE bellhousing to fit, it's not quite as easy as has been suggested. Supply is slim.
If you want more hp, try a vw from 1974-1995, they all use the same bellhousing and are mechanical engines. The TDI also shares a bellhousing but the engine is electronic and more difficult to marinize.
Pathfinder marine used to marinize the vw, look for parts
Someone recommended a popular UK supplier of marinizing parts, that's a great place to start.