250 B&M blower question
 

Is the oil fill plug on top of the blower drive supposed to have a small hole in it?vent? Mine does and it blew oil out of it after running engine for the first time. Possibly the seals are bad on rotor shafts leaking boost into drive? This is a used blower set-up so I'm not sure if the plug is supposed to have a hole in it or not.
Thanks for any advice.

Re: 250 B&M blower question
 

I cannot recall any of mine having a hole.

That plug is the same size as an engine oil galley plug?

This might be reaching but it soundl like someone grabbed a plug from their stash and it was a drilled plug for the oil galley behind the timing gear.

Re: 250 B&M blower question
 

The B&M 250 Blowers are on my 800SC's and the plug at the top of the front case IS vented. The Mercruiser Service Manual confirms this. The fill plug is lower down on the front cover. Fill with 90 Wt. gear lube until it runs out. The book says the 600SC and 800SC have the vented plug which must be kept clean. They say not to paint it or fill it in or clog it in any manner. Holley carbs bought B&M but doesn't support this blower based on what I read. I suggest The Blower Shop for any assistance.

Re: 250 B&M blower question
 

correctomundo on the vented plug... :) Had a 250 myself. It'll only blow over after a hard run, when you find the level. The level so it isn't blowing copious amounts over all the time, will be somewhat below the "check plug" level. You just need to keep an eye on it and throw a couple squits in it now and then. You'll get to "know" it in this regard. I kept an old 7 oz. Rain-X bottle filled with gear oil and an allen aboard...perfect. :)

Re: 250 B&M blower question
 

Profile...

You can put a solid plug in that blower without any problems. I have worked with alot of these blowers. They do come with vented plugs, but we do plug most of them.

Steve

Re: 250 B&M blower question
 

Thanks for all the advice! It did seem to blow out after hard run. This is a new engine and I'm still getting it dialed in. Years ago I had a B&M 142 small block set up on a car and never had a oil problem like this,however I don't recall if the plug was vented on the 142.
Thanks again

Re: 250 B&M blower question
 

I have also rigged a small puke tank on these. So the oil runs back into the case as it cools down. I was afraid of pushing a seal out with a solid plug. The speeds that drive turns, the heat generated, and the relatively small lube capacity was why I rigged vented puke tank. It worked.