75HP Johnson Stinger

[CBFSE107]

The 75 stinger long shaft is different than the short 15" version. The short shaft models were the ones used for racing. They were non power trim. Mostly on Allison, Delta craft, Pipcorn in the FE class. In the SE class they were the standard motor on all with a few Merc 650 still competiting. ( 1975-80) The main difference was the Gear case. The short shaft models had a case they called the Sprint drive. They were a lot smaller than the long shaft version. I expect the long shaft version was the same as the 70 hps. The shorts shafts are the ones to get. Just in case you are interested here are the part # for the gear boot. Short shaft case 385560 pinion 0320114 fwd 0386760 rev. 0320113
Long shaft case 386914 pinion 313343 fwd 387143 rev. 318304.

[Tomtall]

Short shaft

( 1975-80) The main difference was the Gear case. The short shaft models had a case they called the Sprint drive.

Yes you are correct that they were different. They were smaller. The gerafoot used on the SE OPC class I believe was the same gearcase off the 50 h.p. OMC engines as opposed to the stock 75 h.p. gearcase. (correct me if I'm wrong). This was one I sold a few years back (picture) from my stash. Went to someone in Texas.

I know the good Stingers also had a early piston that had a high top ring groove compared to the later versions or even the aftermarket pistons. Those high ring pistons didn't like getting too hot from high timming or lean burn as they would burn the ring land and stick pistons. But they ran good. Randy Minch had a SE tunnel that ran very well with one of those engines.

[form-e one]

mmm and the motor i set the record with was small wrist pin rods as are most my motors gooo fig,,, my understanding the 1975 75 hp had different fireing order,,, mutch my research for v-rude the 65-75 hp was carb jetting.. then the 75 hp, carbs and also the timeing was turned up a bit

[Tomtall]

Form-E

mmm and the motor i set the record with was small wrist pin rods as are most my motors gooo fig,,,

I guess I don't understand what your saying here. So you feel the small wrist pin rods make the engine run better or that's all you had to work with? I would think the small wrist pin bearings would have higher bearing speeds which in theory would hinder higher RPM. Or are the small wrist pin rods that much better do to another reason, like less weight from the smaller wrist pin? Just wondering.

[form-e one]

i turn all my motors around 8k rpm some higher,, if my stupid digitron is right,,, i think a lot of people building there own fe motor forget or overlook is the roundness of the bores and rod ends i have found that the v-rude gets way out of round compared to mercs,,,i dont even balance the parts anymore... to expensive and they gonna vibrate anyway.... found with the big fishing flywheel ie stock ignition,,, they seem to smooth right out.... i only need one tube denture creem per race day hehehe..

[Hunter]

Stinger or not

Tom L ... bearings on wrist pins provide for the rod to rock back and forth as the piston goes up and down so there really isn't a spin of bearings involved. Those smaller wrist pins are located closer to the piston top, hence the rods are longer. That rocking motion is therefore slightly diminished and could reduce the tendency for a well worn piston skirt to bind on the cylinder wallls. The rods are also much lighter than the short standard "A" frame rod. I have a major collection of every piston and rod ever used in the 3cyl omc. I have yet to break any. I have most likely burned up or stuck more pistons than anyone. There seems to be no advantage associated with any particular type. My problems are generally related to improper jetting and poor attention to the cooling loop. I have dismantled some late model Stingers which had the standard heavy rods and pistons.

[Tomtall]

Hunter

Thanks for your explanation. That makes perfect sense.

Tom L.

[Dave M]

Perfect

Tom L ... bearings on wrist pins provide for the rod to rock back and forth as the piston goes up and down so there really isn't a spin of bearings involved. Those smaller wrist pins are located closer to the piston top, hence the rods are longer. That rocking motion is therefore slightly diminished and could reduce the tendency for a well worn piston skirt to bind on the cylinder wallls. The rods are also much lighter than the short standard "A" frame rod. I have a major collection of every piston and rod ever used in the 3cyl omc. I have yet to break any. I have most likely burned up or stuck more pistons than anyone. There seems to be no advantage associated with any particular type. My problems are generally related to improper jetting and poor attention to the cooling loop. I have dismantled some late model Stingers which had the standard heavy rods and pistons.

Hunter, keep the mouth closed. We don't want our secrets out there for all to see..... people will start to think Super E is a cheap class.... and that you don't need to do all that fancy crap. I know I don't, and your post proves two real competitive rigs anywhere in the country agree.... Speed does not have to cost ya tons of cash.