125 Lycoming Ground Power

[midnight rider]

Does anyone have any experience with a Lycoming 125 Ground Power.
I am wondering if these are truly 125 H.P. after having the sump changed out and the cylinders changed out. Mine has:
2 @ 0-435 cylinders
2 @ 0-290D2 cylinders
Sump from a 0-290 and also has 2 mags.
I am currently swinging a 70" sensenich "H" series two-blade set on pitch mark 2 @ 2900.
Has anyone ever had one and had it dyno'd?

 

[Sniper]

I just picked up a o290 g it is probably the same engine you have I was told by a Aircraft guy this week end that if you turn it about 2800 rpm with two mags it will put out close to 150 hp I guess I will find out I would be interested to know what modifications you did to your motor so that you could run it in a Airboat like carb and intake I did get a Aircraft oil pan with the engine which is a start

 

[Waterthunder]

Them cases are beefier and that motor comes with a solid lifter cam and adjastable rockers. When I was a kid there were a bunch of them around here. I like the adjustable rockers in them. They are a cool little cheap motor to hop up.

 

[midnight rider]

I have a MA-4SPA for a carb
the sump is off of a 0-290 aircraft case an the intake tubes are also.
I had to make a little plate for the blow by because it had the puke tube on it. I like the motor, it will push me were ever I want to go. Of course my hull weighs next to nothing an no poly. You should like it if it is set up on your boat right.

 

[Sniper]

Midnight rider

Where did you get the Carb and intake I need them for my motor I did get an Aircraft oil pan with the motor and are you running dual mags ? I also need a tac drive that goes on the back of the motor

 

[midnight rider]

I got the carb from a guy that had an extra. Just found out by word of mouth. I am running dual mags. S4LN-20's. I had everything for the tach already. I believe that this should be the stock carb off of a 0-320H2AD, 160 H.P.

 

[sawsa]

I have what ever you need for the 125's, cranks,cams gears, mags, or whatever, bottom ends and top. west side airboat's 954 325 6892. those motors stock are 140hp, there are tricks to the trade to get more but it cost some money. i have a couple sittin hear that produce close to 200hp, and as far as snap im sure that there aint no other motor that is a 4 cylinder out there that can stay with it.

 

[Sniper]

West side Airboat

Fantastic I will be giving you a call thanks for the information

 

[dblj006]

West Side,
Just curious. What would one of those 200hp motors set somebody back? What kind of mounting do those cases have?

 

[sawsa]

straight mount just like they are , and some have had close to 7 to 8 thousand be cause the 125's parts are hard to find. rings are the worst. alot of these builders are using disel rings that dont work worth a s###.!!

 

[midnight rider]

Have you ever used chevrolet rings, I know a friend that used to work for piper and he said they used them on a lot of ring jobs.

 

[sawsa]

no, but i would like to know what chevy uses a 4&7/8 piston to use and automotive style ring. the disels are the only pistons that i know of that have those size pistons, and when you have steel cylinders thats ok, but when you have chrome cylinders you are screwd. automotive and aircraft dont mix, carbs are a driffent story.

 

[midnight rider]

He told me that each one had to be custom cut down in their shop. I geuss since they had everything their to do it , it was worth it. He said they lasted longer under extreme conditions. I don't know much about machining so it was just advice that was offered to me.