bford1

This weekend I was out and running at WOT for a few minutes. I started smelling some oil burning so I stopped and checked under the hatch. It took me a minute to figure out where the oil was squirting from. At first I thought it was a valve cover breater. But, then I realized that this wasn't motor oil. It was thicker more like gear oil. I am about 95% sure that it was squirting out of the brass plug on the top of the blower. I haven't serviced the blowers yet. I have only put about 50-100 hours on it since I bought the boat and the engines have about 200-250 hours.

Is this a common leak problem on these blowers? Is the case aluminum and should I use a sealer on the plug. What about anti seize? I don't know if it's aluminum or not. The last thing I'd want to do is strip it and have to oull the blower to repair.

Secondly, can anyone tell me what type of service to do on these blowers? (B&M 174s). What type of oil does it take - 80wt.? Is there a synthetic that would be best to use? How much do they take and how can you tell when the blower is full? There isn't a dipstick or window or anything that I can tell. Also, how do you drain the old oil? Do you just have to suck it out or is there a drain in the back?

Thanks in advance for all your help guys (and girls). OSO is awesome!

88Fount33

Some blowers come with tiny hole drilled in the plug to prevent the gear section from building pressure and blowing a seal on the one of the rotors. On OSO some have said that puking some oil out is OK as it then finds the level it can run at without further loss. Others install a small puke tank and hose to this connection to catch the oil. I would not install a sealed plug as the hot oil will build pressure and it is better to puke it out than to blow a seal. From what others on OSO say, I would service the blowers much more often (50 hours tops) with a good synthetic gear oil (look as the oil thread on this page for more info).

HiPerf2000

iTrader: (2)

The 174 holds a very small amount of gear oil. The front plate is alluminum. But, Make sure the oil is not coming from the front pulley area. Mine leaked there and i thought it was a seal, but it ended up being the pulley itself. The seal will wear a groove in the pulley and let the oil leak bye.

I think that i remember there being a "sight" plug on the front face of the blower (below the fill plug). The thermostat housing prevented you from getting to it. I would always just pull the blower off. You have to leave the blower sit upside down in order to drain the oil out of the top fill plug. I used a 80 - 90 synthetic.

bford1

Thanks 88 Fount 33

Here is a pic of the engines and the location of the leak is circled. This isn't just a leak. It squirts oil all over the top of the hatch.

I am confident I could fix the leak with some thread sealant. But, I wasn't sure if these things are aluminum, if so are they heli coils? Etc. I'm sure it's about time to service them anyway so now's a good time to learn how.

HiPerf2000

iTrader: (2)

It is a tapered pipe plug in the top, and it shouldn't leak. It also shouldn't be trying to spit out. maybe it's overfilled?.

The oil only fills that front plate and nothing else. So 1-1/2" wide plate, and the "sight" plug is only about 2" high. So it only takes a few ounces of oil.

bford1

Thank you hi-perf-2000.

I don't think it used to leak so I doubt it is overfilled but it is possible. I have noticed a little oil accumulate around the plug before but it certainly never squirted out under boost like it does now.

Is the front of the blower the only place that it takes oil? I assume ther eis no reservoir in the back. I don't want to remove the blower if I don't have to. I was thinking about just sucking or pumping the oil out and replacing it.

This seems like a minor problem. At least I hope it isn't anything major.

HiPerf2000

iTrader: (2)

Make sure it isn't that front pulley leaking. when it leaks there it flings oil everywhere. could be landing by the plug.

The front is the only fill. The back plate does not take oil....they are sealed bearings. It is not very hard to remove the blowers for service.

bford1

It is flinging oil everywhere so maybe it is leaking from the pulley. I'll check for that also. Thanks again.

Gary Anderson

Virtually all blowers will eventually leak pressurized air and fuel by the internal shaft seals to the front and rear reservoir. I'll bet yours is full of gas contaminated gear lube. Change out the gear lube, refill to the site hole, and check it again in 10-20 hr. You may need the seals replaced if leakage is too bad.

US1 Fountain

iTrader: (1)

My 250 blower did the same thing. But it was more of a very fine mist that would come out of the top fill/vent plug. Same thing as you are showing. It only happened when I would run hard for an extended period of time, otherwise always dry. B&M says it is supposed to be the plug with a small hole in it for venting and NOT to install a solid plug. I talked with the Blower Shop about this and was told it was from heat and possibly blowby past the inside seal. They advised me to do what they do with the 174 and 250's, Use a solid plug and just change the oil every yr. Never a problem after that.