2 OMC Questions

[RFiliau771]

Does anybody know what year OMC started rating their horsepower at the prop instead of at the powerhead?<br /> Then, I was wondering if anybody could explain OMC's version of Loop Charging which I think they introduced in the mid 70's? I had this idea that they captured the unburned fuel somehow and sent it back through the engine. I want to say that I saw this advertised in their brochures around the same time they came out with the Johnson Stinger 70 HP engine. I had access to a Johnson dealer as a youngster and I used to pick up the new brochures every year and read and reread them. Wish I still had them now!<br />Thanks,<br />Rick

 

[jimmbo]

Re: 2 OMC Questions

85 or 86 was OMCs prop rating date.<br /><br />1968 was the year OMC introduced Loop Charging in the form of a 3 cyl 55hp. That was probably the year when they also introduced fuel recirulation. Instead of dumping gas/oil, mainly oil, which puddled in the crankcase overboard, it was now sent to lube the bearings.<br /><br />The Stinger, introduced in 1975 I believe, was 75hp version of the 3 cyl block. It was designed for use on small light hulls and didn't have as much bottem end torque as the 70.

 

[Paul Moir]

Re: 2 OMC Questions

Welcome to Iboats, RFMotors<br /><br />You can read some old brochures at www.old-omc.de . A good explanation of loop charging (vs crossflow) can be found at: maxrules.com/fixtheory2.html<br /><br />Hope that helps!