Omc 25h.p.

[adila]

[QUOTE=JohnsonM50]I use one with a stock lower unit from a 79- 25hp, I changed the propshaft assembly to it from a 22ci OMC 72- 25hp, It has a shear pin set up. I adapt different props by inserting the center hub of old wrecked props.
If your 35 is a thru-hub that wont help but you might be able to get a prop made. The 35 powerhead will bolt onto a late 70s midsection but it might need exhaust holes and the shear pin will need to be drilled to 1/4in.


[/QUOTE
Yes ,my 35 is thru-hub with 14 splines shaft. Thanks 4 answer ...I need splined prop...The old propshaft assembly 4 omc it is a good solution 4 increase the gear ratio (at thru-hubs is 1/2.15 ...).

[NERSTROM]

No problem with removing the ring gear.

[Skoontz]

If you did not know this little cheap trick, lemme say....So lets say you don't have the coin for a hot dog gear case. You are running the old "Club Foot"

You can add a nose cone, and if you remove the reverse gear and shift dog, grind all the teeth off the gear and take the tittie wompers off the reverse side of the shift dog, it's good for 4-700 RPM. You can run ATF as lube but honestly, I never saw any real changes from that.

Back in the day, OMC had a part number for a spacer and one sided shift dog for the V-4 75 HP engines, thus, where we stole the idea from. The trick will work in any gearbox with a reverse gear.

[JohnsonM50]

If you did not know this little cheap trick, lemme say....So lets say you don't have the coin for a hot dog gear case. You are running the old "Club Foot"

You can add a nose cone, and if you remove the reverse gear and shift dog, grind all the teeth off the gear and take the tittie wompers off the reverse side of the shift dog, it's good for 4-700 RPM. You can run ATF as lube but honestly, I never saw any real changes from that.

Back in the day, OMC had a part number for a spacer and one sided shift dog for the V-4 75 HP engines, thus, where we stole the idea from. The trick will work in any gearbox with a reverse gear.

Yep Ive put a cone on long ago- a blob of epoxy, when time came to disassemble I cut it carefully with a fine hacksaw [so now I admit bein a hack] Ive got the dog pinned forward with a drill bit stem [tired of wearin out dogs] Ive though about running it in reverse with a lefty race prop but was advised negatively. And I wondered about makin the R gear a spacer. Q- bein how will the pinion gear and bearing hold up? Its a hydro reasonably lite load.
The good news is its comin apart for a rear bush-seal anyway. Thanks for all your input. Mike

[Skoontz]

There may be others with negative response, but honestly, we had a 24" clever with a mean cup on the motor and ran all summer hard.

The thrust on the pinion is going to be on the gear teeth from the direction the engine is engaged. The bearing surface on that pinion is about 1.5" long, maybe more and it's really not going to be any different than a rear end pinon thrust on a truck.

As far as running in reverse with a left hand prop, I wonder why that would be any harder than forward. Reverse is the same gear, same part number as forward, just in a different spot in the carrier. Prop shaft thrust maybe? I dunno....Curiousity has arisen though.

[JohnsonM50]

On this gearcase the thrust washer/ flat needle bearing setup is much more substantial on forward than the relatively small thrust bushing of reverse and the bush- seal assembly is held in by a locater pin, It would probably self destruct.
That reverse gear has an appointment w/ an axle and a grinder!
This hydro Im runnin for now while my runnabout is down for some overdue upkeep its the airborne on show yer boat pg 2. The re-b I mentiond is for that. The motor sounds very good, it has 4 very definite compressions. you could think crank comp. was cyl. comp. till ya turn it more yet you can turn it by the flywheel taper w/ 1 hand when the plugs are out. Ive only done some test wheel runnin so far. I hope to be done with the boat after next weekend. Im tryin graphite in the aft bottom epoxy.

[RichardKCMo]

OMC ,must have had a secret motor in that era, thought they were 36 , motors being slightly less.
I read all with zest even th B.S.
RichardF

[Skoontz]

Richard:

In all honesty, the 25 HP of the 50's may very well have been 36 cu in. I was 12-16 when dad had that motor, and always thought they were 31 cu in and honsetly never paid attention to that. The mods I am absolutley certain of, I welded the manifold, exhaust and gearcase mounts myself in shop class then planed the surfaces. It was a fun project.

[Roy Hodges]

check with any old timer . the stock outboards had a 36 class for 25-30 hp johnrudes ,at the last it was (i think ) won by 35 hp chryslers . somebody jump in and set us straight , please

[36run69n]

Yes, the early 50,s big twins evinjohns were 35.9ci and rated at 25 hp. the last 36ci OMC was the 1956 big twin rated at 30 hp. speeds were high 30,s to low 40,s on a 13' DU boat. The Chrysler (originally) West Bend 35hp was also 35.9ci and approved for 36 class in 1964. The speeds jumped into the mid 40's. In the early 70's the Merc 402 was approved for the class by this time the 36 speeds had reached in to the mid to upper 50's, with the Merc, I think having a slight edge. thou, both engines were very competitive. Cary wheels 9 3/4 X 15 1/2 were tops on the evinjohns and Record and Carys 10-10 1/2 X 16-17s on the Chryslers. Chrysler gear ratio was 13-21. I don't recall the evinjohns. The merc had a 2 -1 ratio and I think ran 20-22 in. pitch. The class was eliminated for '76 as APBA registration dropped below 50. We did have elimination heats at the '75 nats. in Dayton, if my recollection is right, there were 17 entries. It was a fun inexpensive class to run with parts readily available.