differences between thru hub and non thru hub OMC 25hp

[whosmatt]

hi,<br /><br />i've been looking around for good deals on used 25hp motors and from what i gather OMC made 2 different 25 hp models concurrently (early-mid 80's?) one with thru hub exhaust and one without.<br /><br />anyhow, can anyone verify this and explain the differences (ie displacement, weight, ease of service, lower unit durability, whether one is more desirable)<br /><br />sorry if this belongs in non-repair, i just figured i'd have a better chance of getting some first hand knowledge in this forum.<br /><br />thanks<br />matt

 

[G DANE]

Re: differences between thru hub and non thru hub OMC 25hp

The thru-hub 25HP started coming out around end of 80ies. I think the old lower unit was continued on the commercial models. The thru hub is quiter, and a better design that way. Both are good lower units, and power heads are the same, only I think the thru-hub powerhead was limited a bit, as putting a thru-hub lower unit on a previous non thru hub raises output. Thru-hub must bee a little more fuel effecient too, then.

 

[jimmbo]

Re: differences between thru hub and non thru hub OMC 25hp

The thru hub models would have been recreational models while the non hub models would have been commerical models. Displacement was the same. The non hub exhaust was used because it had better thrust in reverse due to the fact the exhaust was discharged seperate from the prop. Most people think the thru hub system is more performance oriented.