I use a backup generator sometimes. Mainly at night if I'm doing a lot
of machine shop work. About a month ago I noticed my backup generator
was starting to sound like crap. I figured it was time to take the head
and cylinder off and the piston out for a decarbonizing. This thing
really takes an abusing and deserves a better user than I. In the
summer I run it on new SVO and in the winter I mix it 10 or 20 percent
with kerosene. Neither are heated. I've been meaning to get around to
that. Between decarbonizing I pull the injector out about every couple
of months and scrape the 0.050" layer or hard garbage off it that's
starting to block the orifice, interfering with the spray pattern. This
is an Indian copy of a Lister 6/1 CS. It is a very simple single
cylinder unit with an iron piston 4.5" in diameter. Iron seems ideal for
this kind of abuse. I can scrape at it as much as I like with scrap
aluminum and the surface is pristine when I'm done. The piston has a
flat crown. It was faced flat on a lathe and you can see the tool marks.
I mean flat. There are no recesses for valves. The cylinder head is
flat iron too. There's no hemispherical combustion chamber here. Both
of these features make it an easy scrape. It ends up taking most of the
day to do this. (disassembly, scrape, reassembly). I could just pull
the head off and scrape top of the piston and cylinder head, but there's
some deposits between the top of the piston and the first ring that I
like to get. There's also the problem of getting debris between the
piston and cylinder and having it score the cylinder over time. It's
just seems right to take it all the way instead. The two times I've
done this the results were satisfying - easy starting and quite running.
As much fun as this is I'm looking for ways to increase the service
interval.
These liquid cooled engines have no thermostats. Since
they are huge (750 lbs) for their 6 hp output it takes a while to get
the temperature up. When it's really cold out(30's) I've not felt the
engine get too hot to touch even after a couple of hours of running.
Most people running these are using 30 gallons or more of water in a
simple thermosiphon cooling system. This massive cooling capacity adds
to the problem of getting the engine temperature up. It is said that
getting the temp up will aid greatly in running clean and efficient.
George at UtterPower.com recommends a napa thermostat. It's a tiny thing
about 1.25" in diameter that costs $4. The water outlet flange that
comes with the engine is plenty thick to accommodate a recess needed for
the thermostat to fit in and the iron machines very nicely. The
cylinder head has a hole where the flange bolts up to it but it's mostly
blocked by casting that was never removed. I guess they didn't think
it worthwhile to finish the job since the machine has decent coolant
flow already. That hole needs to be taken out to nearly the inner
diameter of the gasket. If done carefully it's easy to get a good fit
with the thermostat nicely clamped between the head and water outlet
flange. I did include a small pinhole, as was recommended, in the
thermostat so that steam would not build up in the head. I guess you
could have a situation where steam build up in the water passages was
preventing water from contacting the thermostat. Maybe the steam
prevents hot water from opening the thermostat and there is a delay
before any water flows and the head gets too hot?
It works well.
The freshly decarbed engine heats up fast even when it's below
freezing. It's a 195F thermostat and that's about where the head is at.
It's too early to say if I'll get a better maintenance interval but I
feel like it's an improvement. I don't think any of this excuses the
cold SVO or SVO mix I'm running. That really needs to get done too.
I pity anyone who is abusing a multicylinder engine this way unless they really like working hard.
