replace fron oil seal on Lehman 120

[KDA]

I have a Lehman 120 with about 6000 hours on it. I usually run at about 1500 to 1600 RPM. The other day I pushed it up to 1800 RPM for about 6 hours. When I looked in the pan in the bilge below the front of the engine there was a fair amount of oil. The dip stick showed I was down about 1/2 to 3/4 of a liter of oil.
I have been advised that the reason was probably the front oil seal. I have run the boat at 1500 to 1600 RPM for about 50 hours since and no evidence of any oil.
I would like to replace the oil seal, if that's the culprit, so I will have the higher revs available should I need them in the future.
Has anyone replaced the oil seal on one of these engines? Is it something a DIYer can do? Will I need any special tools? Any techniques I should be aware of?

 

[RT Firefly]

Greetings,
Mr. K. Is the oil dip stick marked correctly? IF marked too high you may be overfilling which might not be a problem at lower RPM's but might manifest itself at higher RPM's.
Wrongly marked dipsticks is not an uncommon situation and has been mentioned on TF several times in the past.
On our previous vessel, BOTH Lehman 120 dipsticks were marked too high. It took a bit of head scratching to figure out how I would "burn" 1 qt the first 10 hours and virtually nothing the next 40 or 50 hours with little to no change in cruising RPM (1750). On one oil change I very carefully measured the exact amount of oil when refilling and Voila! Mark was 1 qt too high.
Not saying this is YOUR problem but won't cost anything to check on your next oil change AND save you the hassle of changing the seal. My $.02.

Sorry. Can't help you with advice on the oil seal...

 

[Comodave]

Have you checked with Brian at American Diesel? He is the guru on Lehmans. 804-435-3107

 

[Irish Rambler]

Greetings,
Mr. K. Is the oil dip stick marked correctly? IF marked too high you may be overfilling which might not be a problem at lower RPM's but might manifest itself at higher RPM's.
Wrongly marked dipsticks is not an uncommon situation and has been mentioned on TF several times in the past.
On our previous vessel, BOTH Lehman 120 dipsticks were marked too high. It took a bit of head scratching to figure out how I would "burn" 1 qt the first 10 hours and virtually nothing the next 40 or 50 hours with little to no change in cruising RPM (1750). On one oil change I very carefully measured the exact amount of oil when refilling and Voila! Mark was 1 qt too high.
Not saying this is YOUR problem but won't cost anything to check on your next oil change AND save you the hassle of changing the seal. My $.02.

Sorry. Can't help you with advice on the oil seal...

View attachment 157850

You raised a very good point Firefly. So many folk have been caught out on that one.