OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Honda Engines HRU173 SUCKING OIL

Hi guys, my next door neighbour has a Honda HRU173 and it is sucking oil through the crankcase breather tube and into the air box. Is this a sign of blowby because of worn oil rings? Thanks all.

Over filled with oil?

Thanks for the quick response Norm, when I checked the oil level initially there was none in it.

G'day MickyD and NormK,

If the mower was not overfilled or tipped on its side then I would say yes the rings are worn out when the mower
blows smoke all the time.



Cheers
Max.

Can also be a worn exhaust valve guide. I have seen that on walk behinds with Briggs engines that other techs thought it was worn cylinders. But an leak down test should determine it is the cylinder or not.

Thank you for the response everyone, I would say the old girl has seen better days, it runs fine but sucks oil into the air filter box. I will advise my neighbour that he needs to bury it and get a new mower. Cheers.

Mickey, if it is running fine might as well use it till it drops. Plug the hole in the back of the air filter and extend the crank breather up along the handelbar with a bit of plastic hose and see how that goes. Got nothing to loose

Hi Micky and Norm,

You might be having an issue with the breather valve which is located on the engine end of that breather hose.

In behind the plate assembly there is a fibre disc that opens and closes which is probably the culprit, it's probably stuck in the open position.

You have to undo the carby and slide it all outwards so you can get to that plate that's held on with 2 x 10mm bolts from memory.

Cheers,
BB.

PS. But if all else fails I'd follow Norm advise.

Thank you BB, I will investigate that tomorrow for sure. Much appreciated.

I have attached a photo of the culprit, I have removed the cover plate from the valve spring housing and it's only a cover plate, there is no valve as per the Briggs engines. You can see the breather hole in the crankcase on the right of the photo. When the engine is running it's sucking oil into the air filter from there. I really would like to find what is causing this even if it just for the learning.

Thing is Norm if I block off the back of the air filter and extend the tube from the crankcase outlet the oil will only fill up the tube I have added from the crankcase up the handlebars.

That complete cover plate with the valve disc is available from Honda as a spare parts for around $7.00, why do I know you ask ? because I just bought one for my GCV-160

I'm just wondering where these discs disappear to as mine was also missing.

Cheers,
BB.

Mickey,

a lot of old motorbikes had breathing problems and by bringing the tube up higher allows the air/oil mix to slow down a bit and the blown over oil has time to catch on the sides of the tube and then work its way back down into the crankcase.Motorbikes have used this method for a hundred years. This is only a bodge to help extend the life of a dying motor in your case. The problem with the breather hose going into the air filter is that the negative pressure in there only increases the desire for the oil to be carried over into the carby. You have nothing to loose and worth giving it a try. And then you could also fit a catch can to catch the blown over oil and allow it to drain back into the motor but that is probably going a bit overboard..

Cheers Norm, i'll put this one to rest I think and i'll tell him he's floggin' a dead horse. Thanks sincerely for everyones input on this. Cheer all!