Big Leak -Please Help!

[Mini-Arg]

Hi All,

I have an engine leak (HPI Trophy 4.6 stock). After running the car the last few times I noticed what looks like burnt fuel (basically oil) under the engine. There was a pretty good amount of oil there. It is important to note I had been running the car very rich (both LSN and HSN) to reset the tuning process.

Removed the engine and inspected closer. No leak from the exhaust gasket.

I then removed the pull start and the inside of it was covered with burnt fuel/ oil. I inspected the back plate in detail (which was also covered in oil) and it seems the oil is coming from either the back plate screws or the starter shaft opening. It is difficult to tell because the whole area was pretty dirty with oil.

When I removed the back plate I noticed a lot of burnt fuel accumulated. I also noticed burnt fuel when I removed the exhaust, so the car was running very rich…

I’ve recently sealed the back plate with silicone sealer (Permatex Utra Copper) BUT I didn’t really seal the screws.

Could the leak coming from either the screws or the starting shaft opening? What can I do to stop the leak? I posted a few pictures for quick reference….

 

[nitrojedi]

thats normal for engines with OWB's...... they suck !!!!!

basically they will always leak as there isno way to properly seal a crankcase with just a oil bushing like they have...so basically till you install a bumpstart engine you will always be dealing with cranky tuning pullstart engines with leaky crankcases......

 

[Snook Man]

thats normal for engines with OWB's...... they suck !!!!!

basically they will always leak as there isno way to properly seal a crankcase with just a oil bushing like they have...so basically till you install a bumpstart engine you will always be dealing with cranky tuning pullstart engines with leaky crankcases......

My Novas have very little seepage past the starter shaft o-ring when tuned well.

 

[Racer 1966]

Yeah it's not really the OWB that's the problem. Running rich will cause the oil leak every time.

 

[nitrojedi]

My Novas have very little seepage past the starter shaft o-ring when tuned well.

Nova's are the only one that uses a o-ring in the backplate...everyone else reies on poorly fitted shafts and bushing..Nova's are actually as closed to sealed as a OWB equiped engine can be........Some of the other brands are horrendous and are nowhere near sealed....

And yes the shaft and bushings leak like crazy on these engines...if you doubt me just do a little break cleaner test while the engine is running..end of story ! a slight spritz by the backplate or front bearing while these things are idling will usually kill them....... very bad design, and a huge reason why bumpstart engines make more power and tune so much easier then oullstart engines.....they don't have a leaky crankcase like 90% of the pull and roto engines.........

And also...they seal better being rich then lean...run them too lean and the crankcases will start to draw vacuum

 

[Snook Man]

Nova's are the only one that uses a o-ring in the backplate...everyone else reies on poorly fitted shafts and bushing..Nova's are actually as closed to sealed as a OWB equiped engine can be........Some of the other brands are horrendous and are nowhere near sealed....

Yep, already knew that (thus the wink smiley), just giving a shout out for the Nova. They also have a very good OWB that requires very little maintenance, I suppose the lack of seepage through the back plate also helps with that as well..

 

[nitrojedi]

Yep, already knew that (thus the wink smiley), just giving a shout out for the Nova. They also have a very good OWB that requires very little maintenance, I suppose the lack of seepage through the back plate also helps with that as well..

Gotcha.... I am on a little screen..so I didn't see the face...LOL...

Nova's are awesome !!!

 

[Mini-Arg]

Thank you all for the fast responses! I thought the problem was mine so I am glad to read your comments and know that I am not alone out there. Like Race1966 mentioned, I am sure running it to lean did help. Should I then consider getting the HPI Roto Start and replace the back plate? I always though pull start was better...

 

[savage24x]

Thank you all for the fast responses! I thought the problem was mine so I am glad to read your comments and know that I am not alone out there. Like Race1966 mentioned, I am sure running it to lean did help. Should I then consider getting the HPI Roto Start and replace the back plate? I always though pull start was better...

People swear by pull start, but for guys who just like to have a good time, I swear by a roto start. No more blisters for me. F*** that.

 

[Mini-Arg]

Makes sense for me as we'll.....

 

[Mini-Arg]

Update: followed the suggestions here and improved my tuning (I think) and I have noticed a big difference. There engine is still leaking but it is now almost unnoticeable. Thanks for the advice.