Why is the Intruder Crankcase Filling with Fuel?

[mswyka]

1979/1980/1981 Intruder has filled its crankcase with fuel three times this season.  First when we pulled it out of the machine shed.  Second time after getting it running and then letting it set for a week or two.  And now a third time again after sitting for two weeks. 

If we clear the crankcase she runs fine, really well in fact.

I am guessing that we only have two paths - either through the impulse line or through one or both carbs.

No evidence of fuel coming out of the carbs when the sled is running indicating that the flow needles are seating properly.

I now have the impulse line disconnected to see if anything comes that way.

Well, i guess there is a third path through the primer.  I will have to check that too.

Interested in anyone else who may have had a similar experience and what it took to solve the problem.

[Interceptor398]

My 81 Invader will sometimes bleed gas past the needles and it takes a few pulls to get er going. I tend to pull it over a couple times before I choke it to make I I don't make the problem worse.  I think the carb  needles and the fuel pump are the 2 places that can let gas past them if things are not perfect.  Not sure about the primer?? If gas gets into the crank case it is not a happy place.  I DO like electric start!

[Dandb7]

Have you checked your fuel pump diaphragms for tears....might need a rebuild ?

[mswyka]

Have you checked your fuel pump diaphragms for tears....might need a rebuild ?

I pulled the sled into the garage and left everything disconnected last night to see which route was leaking.  Nothing leaked.  It is possible that the fuel has leaked as low as it is going to so I will probably add some more to the tank and continue to watch.

[Interceptor398]

I tend to leave the 81 short of gas in the hope that it will be less flooded.  It has been in the negative numbers here so I have not fired it up for a week.

[gixxer6]

I have had this happen.  In my case it was the fuel pump dumping fuel through the impulse line. 

The primer is located quite high, so it shouldn't be able to siphon.  And from my experience the carbs will leak out the overflow tubes rather than into the engine if the needle and seat are they culprit, plus the original Kaw fuel pumps have an anti siphon feature that should prevent this. 

My money is on the fuel pump...

[mswyka]

The sled has now been sitting for 2 nights and the only observed leakage has been from the primer "T" fitting.  Nothing leaking through the carbs and nothing leaking through the impulse line.  I may just have to replace the fuel needles and the pump just to be proactive.

[Interceptor398]

So today I notice a bunch of wood chips on and around the 81 sitting proudly as the king of the snow pile. Hmmm- time to move her out of harms way.  3 pulls no choke and no pops at all.  Put the choke on and 3 pulls and we are ready to rumble.  No leaks of any kind this time around but I am good with that!  I have an 1886 Winchester in 45-90 and some easy shooting cast bullet loads that can fix that tree issue.

[mswyka]

So today I notice a bunch of wood chips on and around the 81 sitting proudly as the king of the snow pile. Hmmm- time to move her out of harms way.  3 pulls no choke and no pops at all.  Put the choke on and 3 pulls and we are ready to rumble.  No leaks of any kind this time around but I am good with that!  I have an 1886 Winchester in 45-90 and some easy shooting cast bullet loads that can fix that tree issue.

No finer sound than when a sleeping power plant roars to life.

[mswyka]

Last night I pulled the fuel pump and found fuel under the diaphragm.  Swapped in a new diaphragm and we will see how that goes.  Since I was at it, i also swapped in viton tipped fuel needles.  The float arm was slightly out of alignment.  Hopefully both adjustments will get us back in business.

At the moment however i am getting seepage at the primer "T" fitting.  My spring clamps are not working as the space between the barb and the center block of the T is too short for my clamps.  Nylon cable ties are not working as i can't seem to get them tight enough.  I need to come up with another solution.

[mswyka]

I have been struggling with this leaky fitting that I  just couldn't clamp.  Tonight I stole a trick from a recent PEX plumbing project and made my own expansion sleeves.  Used 1/4" tubing over the 3/16 tubing and another odd size tube over the 1/8" for the primer.  Nice tight connections and the dripping is finally gone.  Wish I had thought of this years ago.

[gixxer6]

Genius! 

[mswyka]

It has been about a month since the sled received the new diaphragm and fuel needles.  We have no snow so i will go out and start it about once a week.  There have been no starting problems and no more fuel in the crankcase.  I think that this problem is licked for now and I can cross it off my list.

[Dandb7]

Great news.....will wish you some snow now...!!

[mswyka]

Great news.....will wish you some snow now...!!

Thank you.