# Vaccum Source On A Onan 24hp!!!!!!!!!



## jimmyjam (Mar 16, 2008)

yup u read it right i am looking as 2 where to get a vaccum source off of a 24 hp onan lx990.........i allready tried the natural way as to take the 1/8 plug out of the intake just beside the carb and it has no vaccum but if u blow air in it it blows out the carb ...so that dont make no sense.................now what i need vaccum for is the vaccum/eletric switch i need to activate the fuel solinoid for the propane system for safety ...when the engine quits the vaccum/electric switch shuts off the fuel and all is good.............thank you in advance....:dude:


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## pyro_maniac69 (Aug 12, 2007)

propane system? what for? you doing some hardcore racing?


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## Restrorob (Dec 23, 2007)

Jimmy, 

Standing in front of the flywheel remove the right hand cylinder head sheet metal, Behind it you will see a impulse line for a regular fuel pump. If yours didn't have a fuel pump look at the block in that area and you will most likely find a 1/4" pipe plug sealing the port.

Btw, Had to jump some hoops for this pic only having your Deere model number.












Good Luck


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## 30yearTech (Sep 14, 2006)

pyro_maniac69 said:


> propane system? what for? you doing some hardcore racing?


Racing??
Why would anyone want to use propane for racing, gas engines running on propane fuel do not produce as much power as they do on gasoline.

Probably needs to run the engine indoors or perhaps on a job that specified the cleaner exhaust emissions of LPG.


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## pyro_maniac69 (Aug 12, 2007)

oh ok....if they don't produce as much power, why do they use propane injection in trucks and some cars if you buy the kits?


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## 30yearTech (Sep 14, 2006)

Cleaner exhaust emissions, and LPG used to be much cheaper than gas, but I don't think thats the case anymore.


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## jimmyjam (Mar 16, 2008)

Restrorob said:


> Jimmy,
> 
> Standing in front of the flywheel remove the right hand cylinder head sheet metal, Behind it you will see a impulse line for a regular fuel pump. If yours didn't have a fuel pump look at the block in that area and you will most likely find a 1/4" pipe plug sealing the port.
> 
> ...


yes i have found that fuel pulse hook on my engine but was thinking that because it is a pulse that it would turn the switch off then on all the time but i never hooked it up to actually try it....i will do that first thing mon morni......thank you much for the info :thumbsup:


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## jimmyjam (Mar 16, 2008)

pyro_maniac69 said:


> propane system? what for? you doing some hardcore racing?


nope this machine is a man lift for working in doors and because it will only give off carbon dioxide and emissions are that much lower .......and yes propane will give u more hp then gas being that lpg has a octane rating of 108-112 ..........i have done alot of circle track racing playing with lpg and dual impcos and tha such....very easy fuel to set up and no carb adjustments at all besides idle realyy..........thanks pyro....


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## jimmyjam (Mar 16, 2008)

30yearTech said:


> Cleaner exhaust emissions, and LPG used to be much cheaper than gas, but I don't think thats the case anymore.


right now "30yeartech" we are paying about 1.10 per litre and lpg is 0.65 per litre...lpg for us has allways been about half the cost of gas ..but our deisel prices are 1.20 per litre...getting steep here real fast.........:thumbsup:


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## jimmyjam (Mar 16, 2008)

...........i will post some pics in the next couple days here of the manlift and the setup i did ...just some good info for the people that want to know how this works...thanks everybody and will post tommorrow night and tell the news..............now i must go shovel the walk and bundle up to do that......dang cold here........


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## 30yearTech (Sep 14, 2006)

jimmyjam said:


> .......and yes propane will give u more hp then gas being that lpg has a octane rating of 108-112


Propane will only give more hp on an engine set up to take advantage of the higher octane that propane provides, propane has a lower energy output then gasoline per given measurement, so unless you bump the compression ratio of the engine to a point that higher octane ratings can be advantageous, there will be no benefit. On normally aspirated engine just converting to propane can result in a 10% - 20% loss in power with a slight increase in fuel consumption.


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## jimmyjam (Mar 16, 2008)

... so ok then i used the vaccum pulse line for the vaccun/electris switch and it works great .....until i turn it to high idle then there is to much pulse and it turns the switch on/off...on/off...so the motor idles up and down like crazy....so how does a guy wire it off the oil sending unit if possiable?????????????....other wise this machine runs like a top on lpg these kits are pretty east too...and yes pics are coming when i am done next couple days.....thanks in advance......


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## Restrorob (Dec 23, 2007)

Jimmy,

One of these just came to mind;

http://store.summitracing.com/egnsearch.asp?N=700+115+309801&D=309801

They had something like this (a soup can) on quite a few cars to prevent the drop in engine vacuum from de-activating the vacuum operated trap doors in the AC duct work.

Possibly a vacuum reservoir would lower/eliminate the pulse at higher RPM's ?

Maybe experiment with a piece of four or six inch pvc pipe say about a foot long capped and drilled at each end for 1/4" barbed fittings.

To wire into the o.p. switch you would need a in-line type solenoid instead of the vacuum one and it would depend on the o.p. switch, Some are single up to triple wires and some are normally open while others are normally closed.


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## jimmyjam (Mar 16, 2008)

...well i got it good now.....i went with the o.p. switch ...it was simple enough ..it was closed when cranking and running and open when u smothered the engine..and yes restorob i had a 2 wire fuel solenoid other then the vaccum one so that worked excellent...the machine runs like a top.....the only problem i run into was that the vapour bottles i was sold where only uprights could lay them horizantal!!!!!!!!!...so i call the guy up and he says tuff for you so i tell him to look at the faxed order as to where is says lay down bottles and he kinda sorta agrred it was his fault .....then he says there is a cost diff of 80 more per bottle i tell him to stuff it and call up national energy and they have the right bottle for 125 where he wanted 218 so that ends my dealing with him...thanks for the info everybody and will post pics later tonight


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