minimum temperature for lpg injection

[munkymush]

what is the minimum temperature its possible to run a lpg injection system on ..i have a setup on a ski boat and it runs at 160degrees F which is giving me 60-62degrees c through the vapouriser, its a freshwater cooled system so its not possible to run it any hotter without converting to a closed circuit setup..its running ok at the moment but just curious as to what the limits are?

[woody]

Hi, even if you are using raw cooling from the lake [or sea] you will still or should be using a thermostat.This is what keeps the engine at the correct operating temp.If its only running 60 degrees c or so and takes a long while to warm up , it sounds like a missing or broken stat.
Your engine should,nt take any longer to warm up than your average car.
Check your stat first and go from there.Most boat stats are around 84 degrees or so, so vaporiser temps will only be a couple of degrees lower depending on how far from the engine it is.

hth woody

[demonicwillow]

what is the minimum temperature its possible to run a lpg injection system on ..i have a setup on a ski boat and it runs at 160degrees F which is giving me 60-62degrees c through the vapouriser, its a freshwater cooled system so its not possible to run it any hotter without converting to a closed circuit setup..its running ok at the moment but just curious as to what the limits are?

What engine dyu have ?? merc or vp ... I was gonna add yanmar but then yu probably wouldnt have lpg if its a freshwater cooled system then it is a closed circuit setup cooled by a raw water pumped intercooler, generally they will run cooler than a car engine but not by much

[munkymush]

hya,and thanks for the input .. .. its raw water cooled as you call it .. freshwater was my description meaning open not closed cooling circuit.. it does have a stat fitted and brand new and 160 degs ... the engine temp guage shows 160 when running up to normal temp.. its a chevy block but an indmar conversion ..my take on it is that raw water or open circuit engines do run at 160 closed circuit run at 180 which is the figure you quote woody ...which is why im wondering if im limited on heat supply with being raw water cooled ..160 is 71 degs so im assuming by the time the reducer has done its job droppping to 60 would be the norm ?

[rossko]

What do you think is a problem? You can run a vaporiser at 0C so long as you pass enough water through it to stop it dropping much lower.

[demonicwillow]

It also depends on where your vap is plumbed in ... the headers will be raw water directly fed only the block will be controlled by the thermostat so if the vap is tee'd into a header Or riser I should say then itl run cooler than the block, also are you on a lake or the sea ?? and do you have an anode in the vaporiser ?? aluminium and sea water dont mix very well and its water galleries will corrode and choke up very quickly unless anode protected. Most marine lpg converted installs I have seen and thats not too many have been closed cooled converted to get around this problem.

[munkymush]

its run on freshwater always ..theres no corrosion in the vap, waterways are clear..its plumbed in from a blanking plug at the side of the thermostat housing on the inlet manifold, which is right at the side of where the temp sensor is fitted, and it returns via a y pipe plumbed into the raw water pickup. the y pipe thing is sold by american marine spares suppliers.. to get better flow +heat through the boat heaters.. and it does work the temp is higher with it in the vap circuit with it in ..

[demonicwillow]

Ahh I got you know, just had to do some research on the y pipe thingy, so your engines raw water pump is inboard as would be on a vp probably driven off the crankshaft pully centre, and not within a leg because you probably dont have one so by creating a vacuum and a large one at that cos of the impeller pump and not the circulating pump you get a higher flow at idle, Is fitting a 180f (82c) thermostat an option from Indmar or should it be just a 160f (71c), (dont know much about an indmar chevy instal) if it is then chuck one in or if not your stuck with 160 but I would have thought that was well hot enough for your vaporiser.

[Gilbertd]

I would think the Indmar is going to be very similar to the Volvo Penta as they also use the small block Chevy motor as a base. In fact got a set of almost new hydraulic cam followers in the garage as the motor we rebuilt had a ticking noise that sounded just like a dodgy follower. Replaced the full set only to find the noise was still there until we tried running it with no drivebelt and realised it was the alternator ticking. Buying bits for a small block Chevy is a lot cheaper than buying the identical bits for a Volvo Penta.......

[munkymush]

160 is the recomended stat, but i think there is a 180 if i can locate one i will give it a try.

[classicswede]

I've always found it best to take the water from teh blanking plug for the cabin heater (flywheel end of engine) and dump the water out into the exhaust. The Water to teh exhaust needs about an 8mm restrictor in it to keep the flow down.

In colder weather you need to let the engine tick over for a while to warm everything up but no issues once all is warm.