Wet carburetor gaskets

[Reveller Saws]

I have a saw giving me fits, i have been up and down the list of possible fixes. My latest clue is regarding my carb gasket. I pulled it off and it's completely soaked with fuel, not a dry spot on it. Now in theory I would think that it should come in contact with SOME fuel, but it surprised me that it felt heavier and wet to the touch.

I have built a lot of saws for a hobbyist, but for the life of me I can't remember soaked gaskets. Is this normal or a clue to end this rabbit hole of chasing problems?

 

[mirage]

sounds like it is getting to much gas. Time to take apart the carb and clean or rebuild.

 

[Reveller Saws]

sounds like it is getting to much gas. Time to take apart the carb and clean or rebuild.

Thanks!
So carb 1 is cleaned with an oem Tillitson rebuild. That's the one that came on it. For a control, I installed a 288xp carb (swapped linkages). Ran exactly the same on either carb.

Any other fool would have sold this saw for parts by now. Runs fine upright, for as long as you want it to. I wouldn't be surprised if you could idle through a whole tank.

Tip it right, it floods, left, it starves. I have replaced bearings, seals, o-rings, fuel line and run pressure/vac tests on the carb/case/fuel line it holds just fine. USUALLY, when I see an air leak the tune walks all over the place. This saw will run and cut FINE all day as long as you don't ask it to idle for long tipped to the right.

I can hold it wide open in any position and it never runs away, seems like this is only a problem at idle speeds.

 

[Funky sawman]

Inlet needle arm sounds too low, raise it .005" and try the tune a little leaner on the low side

 

[Reveller Saws]

Inlet needle arm sounds too low, raise it .005" and try the tune a little leaner on the low side

I tried, thanks for the tip. No luck, same symptoms. I think it might be time to dunk this saw, as much as I don't want to. Lookout bathtub, this might leave a film.....

 

[davidwyby]

@Stump Shot is pretty savvy at shooting trouble

 

[Stump Shot]

Usually when tipping a saw and it changes lean or rich means a leak and usually through the seals(Even a new seal doesn't perform as it should if the spring falls off in placement)
Quite normal for carburetor gaskets to soak up fuel/oil mix they usually swell tight which makes them harder than when they went in. Even a new slightly leaking carb gasket can swell itself shut and seal up after fuel has been out to it.
A pressure test on the carb and a pressure/vacuum test on the case will tell what goes on right quick.

 

[cus_deluxe]

did i miss where u said what saw?

 

[davidwyby]

did i miss where u said what saw?

prolly 181-281-288

 

[cus_deluxe]

i figured, but ya know what assuming gets ya haha

 

[Reveller Saws]

prolly 181-281-288

I have had nothing but excellent luck with my 288 builds, no this is an 84 Jonsered 630.

Did a fresh round of vac and pressure testing last night, it's SOLID, several minutes of hold on the carb, crankcases (rotated the crank as well), and fuel line. Put it together with a fresh carb gasket and ran it this morning, still the same exact symptoms. 10 in hg, 7 psi pressure. Tipped the saw left and right. I have done the brake cleaner trick like David did on his, nothing notable there.

I have found leaks and changed seals on probably 3 dozen saws, but this saw has me doubting if I should even be allowed to change air filters.

One thing I have always wondered, does the lean/rich of the tip give a clue to the problem side? Goes rich with the bar side on top, lean with the bar down. Does not die when tipped forward after idling a while like it's pooling/too rich.

I think my next step is to track down oem crank seals, I am currently using aftermarket.

 

[davidwyby]

Wet gasket is between carb and intake?

Fuel pickup issue seems like…

 

[Reveller Saws]

Wet gasket is between carb and intake?

Fuel pickup issue seems like…

Yes, carb to intake gasket.

Im not familiar with the term, do you mean regarding fuel line/filter? I have swapped that out once, but it does seem like a likely answer, just can't figure out how to make it any better than I have it now.

 

[davidwyby]

My 288 filter gets stuck high in the tank when I flip to one side sometimes

 

[Reveller Saws]

My 288 filter gets stuck high in the tank when I flip to one side sometimes

Got in there and put an oem length line in, couldn't make the filter fall to the right side when tipped. Shortened the line, still not 100 percent on the bench, but hoping when it's running it plays nice. I'll fuel it up and start it later, I hope this is it.

I'll be in Phoenix twice this year, if I end up with a long layover I might bring this saw to you so that we can run it over with an army truck.

 

[Stump Shot]

@Reveller Saws
A loose throttle rod from wear could give run issues like you spoke of.

 

[Reveller Saws]

@Reveller Saws
A loose throttle rod from wear could give run issues like you spoke of.

So with the cover off I would see that in action? Or is it just a replace And see situation

 

[Stump Shot]

So with the cover off I would see that in action? Or is it just a replace And see situation

You might, sometimes they wobble to and fro and sometimes even back and forth if the throttle plate gets in on the action.
Not a common occurrence, does happen now and then on a well used carburetor.

 

[bertfixessome]

Did you change the piston ?
sounds like a porting problem causing reversion at the inlet manifold
How & where did you block off the ports to do your pressure tests ?
Originally used to blank off the inlet by sandwiching the rubber between the carb & manifold
Amazing how many leaky manifolds I found this way .

 

[Reveller Saws]

Did you change the piston ?
sounds like a porting problem causing reversion at the inlet manifold
How & where did you block off the ports to do your pressure tests ?
Originally used to blank off the inlet by sandwiching the rubber between the carb & manifold
Amazing how many leaky manifolds I found this way .

Well, as fun as it sounds, I have never tried to alter a saw from stock in any way. Clearly I have my hands full just making a saw run correctly ....
I am leaving the manifold bolted to the cylinder and blocking at the back of the carburetor. It's a bit maddening to me that I cannot test the carb to manifold gasket, other than spraying with brake cleaner.

I really hope it's the fuel line getting stuck. Not that I have a good answer to what to fix that with, but at least I could identify the villain.

I have approximately 15 saws of all sizes, all of them were trash saws or cheap finds. Some only needed fuel lines, all the way to built from discarded parts boxes. None of them have fought me like this saw. It's my greatest foe.