What oil do you use in a B&M 177 test drove for the first time today and they spit oil out of the hole in the top plug/vent on top of the blower I used synthetic 70w90 gear oil. I filled them to the bottom of the fill hole eng ran fine other than the oil loss. I also changed to a set of cleavers 15 7/8 from 16.5 choppers now I cant plane unless I turn them 5500 to 6k Chris cat with no2 drives.

I had the same problem with my 250. I have been just running a solid plug last 3 yrs, no problem. I called The Blower Shop last month about this very thing. They said the rotor oil seal is a single lip seal. Keeps oil in, but doesn't prevent pressure blowing by it when you get in the boost, which is what is happening here. They said it was recommended to them by B&M to just use the solid plugs. I know, the manual specifically says to use the vented plug, but , they now say to. The guy BS guy said to just change your SC oil every year now.

Jerry

oh yeah, 80w90

The guys from The Blower Shop worked at both B&M, and Weiand before they got bought out, so they know what's going on. Double check, but they told me NOT to run synthetic in the blowers, it's too thin. Told me to use regular old mercury gear lube in the 250 I just got from them.

Doug

Did you overfill? My 8-71s get filled to the oil level hole on the front of the blower, not the bottom of the fill hole on the top of the blower. I use Merc Hi-Perf gear oil.

I called Holley tech today waited on hold for a good 30min they said not to run syn oil to run reg 90w said nothing about using a regular plug. I have a big jug of the merc stuff I used GM 70 90 syn Probley more like 50 or 60w. I will try heaver oil first and then the plug I have a front cover leaking fixing that tuesday after work. Wont run the boat untill friday unless I drive down again Thanks For The Input!!!!