Looking for ideas on a 45 hydro motor

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MikeP

Well-Known Member
Joined
Mar 13, 2002
Messages
1,460
I have been thinking about trying a 45 airplane motor in a 45 hydro as a inexpensive start for a new boater here to play with.

The goal is convert it to marine use, run it within the limits of the motor in a FF45 hull and get 50mph.

Need help picking a motor, or tell me I am up in the night as it will never happen.

MikeP
 
I have been thinking about trying a 45 airplane motor in a 45 hydro as a inexpensive start for a new boater here to play with.

The goal is convert it to marine use, run it within the limits of the motor in a FF45 hull and get 50mph.

Need help picking a motor, or tell me I am up in the night as it will never happen.

MikeP
I have a k/b 45 drum rotor geraghty preped fresh for $100. plus shipping includes a nice header....Mike
 
I'd go with Mike's engine. Plane engines just aren't the way to go. Most are made for low percentage nitro and the HP and RPM isn't anywhere close to what you'd need to hit 50. His sounds like a bargain, especially if Rod worked on it. Jump on it before someone else does.
 
After experiencing what a MAC45 can do to a FF45 I really think much less motor in this hull could still be fun.

Mikes K&B certainly fits the cost but I would still be asking the same question.

Mike
 
I still feel that a plane engine would be a waste of time and money. If he needs to get used to the speed, you can adjust it so that he doesn't have WOT until he gets time in on the boat.
 
After experiencing what a MAC45 can do to a FF45 I really think much less motor in this hull could still be fun.

Mikes K&B certainly fits the cost but I would still be asking the same question.

Mike
As Ron has already said, it's just not worth the effort to convert a plane engine to marine use. About the only marine use an airplane engine has is for airboats. A much better choice for the FF is to just buy the K&B that's already been offered, or any other older, but perfectly good, marine .45. If the K&B doesn't float your boat :p , PM me, I've got an OPS .45 with pipe that might be for sale.
 
Been there and done that with the airplane engines. This is good if you just want a play toy and not a race boat. 50MPH will be a challenge with the cheap .45 airplane engines.

Rememer that you still need to add a exhaust header, water cooled head, and flywheel before you get to what you have with a marine engine. AND once hes ready to advance, the engine will need to be tossed (no upgrade path)

With a used in good condition marine motor (like the K& B) , you can do things like backoff on the head clearence (compression), lengthen the pipe, run rich, and put a mild prop (stock 1457) on the boat to tone it down.

Or easier, just adjust for throtle so it the carb doesn't go full open.

If you do this, that K&B would last forever with proper maintainance.

Once he's ready to step up, put things back to where they should be and let it rip. As long as your don't puch the RPM too high the KB should be good.

I started out with a OPS 45 that I picked up on clearence for $180 and it is still running today (15 years later).
 
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After experiencing what a MAC45 can do to a FF45 I really think much less motor in this hull could still be fun.

Mikes K&B certainly fits the cost but I would still be asking the same question.

Mike
The guys are givin' ya good advice. Buy that K&B. Rod does real nice work, you will be on the winning end of that deal. And like it was said, just limit the throttle travel at first to get 'em started. :)
 
Been there and done that with the airplane engines. This is good if you just want a play toy and not a race boat. 50MPH will be a challenge with the cheap .45 airplane engines.

Rememer that you still need to add a exhaust header, water cooled head, and flywheel before you get to what you have with a marine engine. AND once hes ready to advance, the engine will need to be tossed (no upgrade path)

With a used in good condition marine motor (like the K& B) , you can do things like backoff on the head clearence (compression), lengthen the pipe, run rich, and put a mild prop (stock 1457) on the boat to tone it down.

Or easier, just adjust for throtle so it the carb doesn't go full open.

If you do this, that K&B would last forever with proper maintainance.

Once he's ready to step up, put things back to where they should be and let it rip. As long as your don't puch the RPM too high the KB should be good.

I started out with a OPS 45 that I picked up on clearence for $180 and it is still running today (15 years later).

Thanks for all the replys, I guess I needed to hear "been there done that"

Unless anybody has any good sucess stories using 45 airplane motors I am done with this idea, think I will go mold something.

MikeP
 
Been their and done that too :wacko:

Had a blast !! running a Magnum .40 that had a water cooled head cap. (K&B 7.5 :D ) machined down stock heads fins. Ran it for years in an old .21 tunnel hull with engine used as an inboard.

Also done a Russian MVVS .40 as a marine conversion in a sport 40 hull. It ran fine too but both really lack any top end punch, 18K to 20K is about it.

The K&B ... The way to go IMHO.

Scott
 
yeap, what dan said, dan remember when we were at the pond running that 40 airplane motor. we were at the edge of the pond with just about ten feet of clearance looking over and around the grass at the boat. lol those were the good ole day. the ops 45 that dan is talking about , i still have it if you would like it i will let it go for $100 plus a pipe.
 
yeap, what dan said, dan remember when we were at the pond running that 40 airplane motor. we were at the edge of the pond with just about ten feet of clearance looking over and around the grass at the boat. lol those were the good ole day. the ops 45 that dan is talking about , i still have it if you would like it i will let it go for $100 plus a pipe.

Like it was yesterday. That was the days of a new boat avery two weeks (pre "Hornet Hydro" days). Swimming for boats. Falling out the pickup boat. :lol: And 15% RedMax castor blend was our HOT fuel. We were scared we'd burn up a motor if we leaned it out. :lol:

Glow plugs would last forever!

It wasn't til we started going fast that all the cusin started. B)
 
MVVS marine engines 159 - 249

http://morrishobbies.com/default.php?cPath...c2c1498a1e562a7

40 size

3071.jpg


45 size

3075n.jpg
 
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