250 to 270 Lower

I believe my outdrive is a 250. On the last trip home while backing into the boatport I grazed a tree with my foil and it took out the anti-ventilation plate.


I have the pieces and could epoxy them back on with some glass reinforcement. Or I could take the lower section off and have a shop weld the pieces back on. I do have a spare drive, but it's for a 4 cylinder and I'm 8, so I'm thinking that might be a lot of trouble. The last option would be to buy a used V8 lower unit and put it on. A replacement wouldn't be much more than what it might cost to have a shop do the welding and perhaps I could use a newer unit like the 270?



Would the 270 fit? Would there be any value to upgrading to a 270?

And for the record, this is a houseboat that rarely sees speeds above 10 mph even though it's billed at being able to hit 30.

And for the record, this is a houseboat that rarely sees speeds above 10 mph even though it's billed at being able to hit 30.

Click to expand...

If you rarely take it above 10 mph, you'd be ok leaving it as is if it wasn't for the missing pieces surrounding the exhaust outlet housing!

If you do change lower units, it is imperative that you match ratios and go through the shimming procedure.


4 cylinder = 2.15:1
inline 6 cylinder = 1.89:1
V-8 = 1.61:1



The lower unit that you show in your last photo is a 280!

The advantages with a 280:

you can use the 16 inch diameter propeller.
you can use a short or long hub propeller.
the trim fin/torque tab is more effective and is equally effective for both RH and LH props.
280 hypoid gears -vs- the 250 bevel cuts gears..... (much more quiet)




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Thanks Ricardo...I think for now I'll epoxy/glass it back together and keep an eye out for a 280 lower.