another dumb omc stringer ?

[66mstgfsbk]

i have a omc stringer 84 with a 305 chevy. the question that i have is the exhaust is not completly going through the hub on the prop. it is leaking at the point where the drive mates to the inter. housing when it is down. is that normal? some exhaust comes out the prop but not all. the reason im asking is i changed my prop and lost speed almost 15mph at wot and trying to pinpoint the cause. thanks for any help.

 

[zbnutcase]

Re: another dumb omc stringer ?

There is a rubber seal on exhaust outlet of the upper gearcase; check to see if its there. But as the thru prop is designed to pull exhaust out at high speed and the upper is out of the water when on plane, sounds like wrong prop to me. And you can't always believe the pitch stamped on it as props are frequently repitched by shops without being remarked. 'nutcase

 

[WizeOne]

Re: another dumb omc stringer ?

It's not the Stringer that is Dumb, with a statement like that it is most likely....well you get the picture!

The OMC intermediate exhaust port has a relief cut in it that comes out below the anode. It is there to reduce backpressure when the boat was at a standstill.

This relief works regardless of what prop you put on the unit and has nothing whatsover to do with your loss of speed.

You could take that little rubber seal out of the outdrive exhaust entry port and it would make just about zero difference on how much exhaust leaves via the prop hub or the relief port.