250SHO lower unit

[jchern]

Has anyone heard of lower unit troubles on a 250 SHO while running a Mercury revolution 4?

[deepsouthtech]

I ran one for almost a year without issue. 23 pitch

[brune90]

heard of multiple problems with the lower units on these motors but non of them were running that prop.

[Headhunter]

Have one on my 200SHO for about a year. No issues I am aware of. Do you have some specifics?

[jchern]

Headhunter,

I haven't had any problem with my boat but a friend who is running a HPS with a 250SHO and a rev 4 23pitch was made aware of potential damage to the lower unit(blown seals)due to the size of the prop. He is getting great numbers but is only reaching 5300/5400 RPM's at WOT.  He asked that i post on the forum in case others had experienced similar issues

[linesider 159]

I wouldnt want to be spinning an sho at 5300-5400. They need to be spinning at or close to 6000 not only to stop from making oil, but also usually make most power at that rpm. HPDI's would be fine at 5300-5400. 

 

Only thing i heard with rev 4's was hubs melting, but no lower unit seals

[Headhunter]

Sounds a little strange and he should be turning close to 6000 rpm lightly loaded

[mulligan]

I can not speak of the SHO lowers but the HPDIs prop seal setup could be prone to loosing oil.  The way Yamaha has the seals both of them  face outward to keep the water out but could allow oil to be slowly push out.  Mine was doing just that until I put the seals in like every other motor out there, one facing in and the other out.  My new lower which is less than a year old is start to loose some oil now so soon I will be flipping the seals around.