Extra Vacuum Line

Patient is a mid 80's Hyster H80E

We just rebuilt a short block 250-6 for it a few months ago.
We are geting kind'a stainky exhaust, and we have one vacwm line that doesn't have a home, and it does actually have vacwm on it.
However - I'm not finding where this should go.
The advance pulls off another line on the other side.

Figger this line out and maybe I git rid of my staink!
Maybe I'll just plug it.... ???






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Think Snow Eh!
Ox

Are we looking at the line above the hose clamp or the dangler below the clamp?

It doesn't look like it in the pic, but the one above is hooked up and goes to the PCV system.

I don't know LP carbs, and so I don't know what the feature is that this line is pulling off of - ass_u_ming that it makes a diff?
I guess that's the root of the question... If this feature has any need for this line?

The end of the line doesn't seem to show that it has been hooked up to anything prior.
I didn't tear it down myself this time, and it sat a cpl weeks under duration, so ... should'a got a pic....


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Think Snow Eh!
Ox

This is a photo of a propane carb on an old L83p Yale with a slant 6 Chrysler engine. It's not your model but propane carbs are similar in function.
There are two vacuum lines in the photo. One goes to the vacuum advance on the distributor and the other goes to the intake manifold at the base of the carburetor port below a spacer then loops back and goes back and attaches above the spacer at the level just below the throttle body plate.

If my explanation isn't clear I'll try again.

This photo shows the other attaching point. It just loops back.

Ox
In your photo there is a larger hose tucked in behind that clamp that looks unhooked. Could the smaller vacuum line slip inside that hose.
Edit. I see you already explained that hose is attached.

I plugged it, and when I came in from outside, I think I still smelled it, so ...


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Think Snow Eh!
Ox

After the rebuild have you adjusted the carburetor? my thought is you have much more engine vacuum now so it is pulling a little more propane out of the vaporizer.

No.
Not adjusted anything.


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Think Snow Eh!
Ox

It probably is NOT a case of mixer adjustment, as propane mixers respond to vacuum regardless of state of engine tune. They generally only have one adjustment (power) which only has effect at full throttle, full governed speed. SOME might have an 'idle' which usually doesn't impact mixture, it simply adjusts minimum bias on the demand regulator so that it reacts to off-idle transitions.

Ox... the stank... does it make your eyes burn, or generate soot out the pipe?

The device below the mixer MIGHT be a 'velocity governor'... but without a better angle, it's hard to tell. Velocity governor is a secondary venturi downstream of the mixer venturi and throttle. There's a vacuum tap point IN that venturi that actuates a vacuum motor and usually a dashpot that either closes a secondary throttle OR... pulls back on the main throttle... to 'softly' prevent overspeed. That vacuum port you see, MAY be the signal source for secondary throttle.

It may ALSO be ported vacuum for the distributor's advance port.

I would place a more likely bet that the stank is a result of improper ignition advance... and I would NOT be surprised if the distributor you have in there, has either been rebuilt, or replaced with an incorrect (probably automotive) unit at some point in time. The base timing and advance for propane is NOT same as automotive gasoline, so if the original distributor was set up with vacuum RETARD and fixed advance, but the distributor you have was from a pickup truck or boat (yep, 250 Chevy = MerCruiser 165) then you've probably got an entirely wrong timing/advance situation.

DaveKamp said:

The base timing and advance for propane is NOT same as automotive gasoline, so if the original distributor was set up with vacuum RETARD and fixed advance, but the distributor you have was from a pickup truck or boat (yep, 250 Chevy = MerCruiser 165) then you've probably got an entirely wrong timing/advance situation.

Click to expand...

This fits.

An acquaintance proudly ran a Chev P/U (350 V8) off EITHER mogas or "CNG" (not the same as propane, but still..) and his underhood swap-over resources and procedure included dual-mode ignition timing set to suit the fuel in-use.

I doubt the distributor has been replaced.
I see no reason that it would have.

It's a 1984 or '85 model (last year for the 250 in Industrial app) and I bought it in the mid 2000's prolly?

However - it was originally a gasoline motor. May still be some gas in the tank?
It was a brand new conversion to LP when I got it.
So - could be that the distributor aint exactly right - but I'm not taching it out to 4500 before I grab another gear, so .... ???

But more the case is that it didn't use'ta stink, and only the shortblock is different.


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Think Snow Eh!
Ox

Ox said:

I doubt the distributor has been replaced.
I see no reason that it would have.

It's a 1984 or '85 model (last year for the 250 in Industrial app) and I bought it in the mid 2000's prolly?

However - it was originally a gasoline motor. May still be some gas in the tank?
It was a brand new conversion to LP when I got it.
So - could be that the distributor aint exactly right - but I'm not taching it out to 4500 before I grab another gear, so .... ???

But more the case is that it didn't use'ta stink, and only the shortblock is different.


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Think Snow Eh!
Ox

Click to expand...

Other than "casing head" gas right off the heads of our old wells up WBGVA way, dunno how yah get "gas" as-in gasoline into a Propane tank?

And... long block OR short, I ain't never yet been able to doo that sorta swap without pulling all the fuel-ly and sparky and hosey and belty stuff, so who knows what went back where it was meant to?

Page Two:

Most fuel gases are dosed with an ultra-high-stink additive for leak warning. Usta bee "mercaptan", but sumthin' else is used now. Rust or water in an old tank degrades that warning stink, new or purged tank, fresh charge, not, and a tank frequently left LOW can concentrate it, too. Park the bugger outdoors, off-side of yer space, let it run a while, issue might could cure itself?

"We" still don't know if it is over-lean NOX stink (acrid, acid-forming, lung and eyeball burning, brown colour if severe enough to be visible at all) over-rich unburnt fuel stink, (invisible to blue. grey, or black..), glycol coolant leak stink (invisible to white, sweet-smelling), or leak-warning tattle-tale leftover stink?

Anybody near you have an owd-skewl exhaust gas analyzer?

Page Three:

Not a motor in my ken, far too many years, FL or other - but that booger dasn't perchance have a (residual provision for...) a vacuum-modulated choke / cold-idle rig on it?

DaveKamp said:

It probably is NOT a case of mixer adjustment, as propane mixers respond to vacuum regardless of state of engine tune. They generally only have one adjustment (power) which only has effect at full throttle, full governed speed. SOME might have an 'idle' which usually doesn't impact mixture, it simply adjusts minimum bias on the demand regulator so that it reacts to off-idle transitions.

Click to expand...

The last vaporizor I bought for a forklift was a replacement part with an adjustment specifically for worn, low vacuum engines.

Ox, lets see a picture of the vaporizor as well.

Ok, on that note, might I add that a yr and a half prior to the new shortblock, that the harmonic balancer fell off. The original unit failed doo to rubber degredation and the outside ring simply fell right off of the center half. I replaced the balancer, but it didn't take a bolt to hold it on, and I expected that the PTO shaft that bolted onto it to drive the rad fan held it on ..... but two years later I found out differently as the balancer fell off.

Then the snoot on the crank was buggered, but it ran fine as was, other than no water pump and no alternator. So, to the issue, we ran for a long time with no coolant flow to the evaporator. It froze up many times. Quite honestly that is about the only reason that we replaced the shortblock. This time I drilled and tapped the crank for a bolt!

I prolly shouldn't say that it didn't staink at all before. It has happened that I (we?) have gotten a headache if running it too much indoors. (6000' shop) But it seems like [the smell] is noticably worse now, not that I've gotten a headache since for sure, but ...

.... Actually my BIL had said before when we got the nasty air that he thought that doo to the cold evap, that maybe some liquid LP was getting through?

Is that possible?

So you're thinking that maybe we need to replace the evap?


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Think Snow Eh!
Ox

Ox said:

no water pump
...
maybe some liquid LP was getting through?

Is that possible?

So you're thinking that maybe we need to replace the evap?

Click to expand...

I'm thinkin' also that when you say "short block" (store-bought?) you hopefully also did at least shade-tree grade "top job" as to cleaning up the valves, guides & seals?

Buggered valves are notorious for failing to fully seat, have TIME enough at low-RPM to leak-back and bugger-up the stinchie-ometric fuel/air ratios, yet run fine at higher RPM and loads or basic momentum covering up the leakage in shorter time-windows.

2CW

Not store bought.
Local shop built it for me in his spare time.
These days he mostly works on big diesels.

Also - he redid the head for me ... 3 years ago?

This is a gear drive truck with 3 speeds, and I lug it at or off idle mostly.
I don't wing it hardly ever.

https://www.practicalmachinist.com/...oxs-shop-08-a-167493/index28.html#post2803115

https://www.practicalmachinist.com/...oxs-shop-08-a-167493/index46.html#post3321564


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Think Snow Eh!
Ox

Ox said:

I lug it at or off idle mostly.

Click to expand...

...and that's actually harder on valves than most folk realize..

First came to my attention with the p'lice cruisers of our local constabulary.

Back in the era of older, more power-hungry electronics, most spent the greater part of their life at idle to keep the "emergency pack" from killing the batter(ies).

You might try playing with the ignition timing.
Crank in as advance much as it will take. Engine knock or balking when cranking and back it off a little.

If you have the Impco VFF lock-off, check for fuel in the vacuum hose. (Vacuum operated fuel lock-off.)
Little tiny O ring can leak fuel into the vacuum line, mostly at idle.
Runs very rich at idle.
Take the vacuum line off while running and see if it runs better.
It should die after about 15 seconds or so.

Thanks.

That is how I set timing.

Will look into the other when we git a chance.
Thanks.


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Think Snow Eh!
Ox