422 engine

[BobRip]

I have been studying the service manual and can find no difference in the engines except the HP and Torque Specs. I am guessing that you think if you move the spring you can change the horsepower. It makes some sense. I wonder what the spring position on the 425 engine is. Does anyone know?

You would also have to adjust the speed stop to raise the RPM.

I may have moved my spring in the wrong direction if your theory is correct

 

[Phils]

Ok, the small spring on my 422 is in the same position.

The large inner "rod" is in the hole closest to the bend.

I'm out of warranty. I hope this is all gonna make sense by the time this thread reaches page 3.

I have had SOOOOO many small engines. Remember, I'm "off-grid" and have had (and still have) generators for times that solar can't keep up. I have never had a grasp of what the different holes would do, or were supposed to do. I've played with some of them before but not enough to understand the basic concept of ".... move THIS one OUT to INCREASE ..." and "... this one IN to DECREASE...." or vice versa or ?

Glad you brought this up, Beechwood.

Phil

 

[Beechwood]

I may be wrong. I know I moved the spring one hole over. I am now not sure of the direction. I noticed in the service manual that the spring is shown in the middle of the 5 hole pattern. Sorry for the confusion. These engines are all identical, but there must be something different.

I now think it was originally in the middle hole and I move it out one hole.

Yes- there is something different, but someone will have to study the parts manual to figure it out!
If anyone cracks the mystery I'll buy the first beer or cocklail of their choice at the pt forum 1st. reunion being held at the govenors ball room in East Overton NJ. April 1st. 2007.

 

[Beechwood]

Hey guys;
Heres a little riddle and hint to ponder! -- HAVING TWO OF THESE IS ALWAYS BETTER THAN ONE.

 

[BobRip]

Yes- there is something different, but someone will have to study the parts manual to figure it out!
If anyone cracks the mystery I'll buy the first beer or cocklail of their choice at the pt forum 1st. reunion being held at the govenors ball room in East Overton NJ. April 1st. 2007.

The following parts are different:
Piston
Connecting Rod
Crankshaft
Governor Springs
Baffles
Carburetor
Throttle Shaft
I may have missed something.
I won't go to New Jersey (just kidding)
More changes than I would have guessed

 

[cqaigy2]

The following parts are different:
Piston
Connecting Rod
Crankshaft
Governor Springs
Baffles
Carburetor
Throttle Shaft
I may have missed something.
I won't go to New Jersey (just kidding)
More changes than I would have guessed

Well it looks like a couple of those things would change the total displacement of the engine like the piston and connecting rod. Seems like the governer would make a change on the max rpm of the engine.

Hmmm april 1st in New Jersey.

 

[J_J]

Mine used to be in that hole. I moved it one inward to get a little more horsepower under load increases. (Boy that will create discussion)

What you are doing by moving the governor settings, in to allow the engine to run at a higher rpm, and therefore give some additional hp. Have you considered the fact that the engine was setup to get the highest torque at a certain rpm? In a lot of cases, more rpm is not necessarily better, and may shorten the life of the engine.
Just my thoughts. Perhaps there is a small engine engineer on this forum and can set us all straight.

 

[MossRoad]

Darn torque curves!

 

[Beechwood]

Hey guys; Remember according to the engine specs. on the 63, 64, and 65 the bore, stroke, compression ratio, and displacement are all the same. So the increased torque curves on the 20 & 22 Hp engines over the 18 HP engine must be created by other means, without increasing the RPM's beyond the designed limits.
When we were all younger ( pre-computer chip era ! ) and wanted to tweak our car engines for a little more power what were the 1st. two change outs we did for not too much money ?

 

[KMA]

I found this in an article on the web:

The EH72 engine tops out the Robin twin-cylinder lineup, which includes the EH65 (22 hp), EH64 (20.5 hp) and EH63 (18 hp). "Our V-twin cylinder engines were originally designed for 25 hp and derated," said Brad Murphy, direct marketing manager at Robin. "The 25 hp model was originally developed for an overseas application and was not originally intended for the North American market."

Think we could find a way to "de-derate" them?