Thorp Air Command - T18.net

Looking for some feed back on a primer system set up.
Those with carbs, and that need a engine primer.
Been trying to keep things simple, but I to need prime when its cold.
Electric or Manual ?

MG

I have an electric primer so I have no room to talk, but guys over on the VAF site talk like they don't need primers in any sort of cold weather. They just pump the throttle (accelerator pump in the carb) while the prop is turning over. If you install a primer, I would think a plunger would be the way to go if you're looking for simplicity. If you go electric, you'll have a solenoid to wire up, a new switch to install, and install a new breaker for that solenoid. I guess you could use an inline fuse, but I like to see the breakers.

That's what I normally do, pump the throttle while cranking.
I've had a few times when it doesn't kick and I run the Battery down
and no start.

Like you said, the manual primer would be the simplest.

Thanks

During my building process I installed the Vans electric primer . At the time it seems like a good idea as it would have been a PITA after everything else FWD was installed . I only used it a few times as I found that even using the primer for 2 seconds would "flood" the engine . After that I used the standard Piper starting procedures . "Crack" the throttle about an 1/8-1/4" During my last annual I removed the Vans electric solenoid and copper primer lines .

As a side bar I was taught during my PP training NOT to pump the throttle on an up draft carb as fuel could puddle in the lower cowl and with a back fire you have Muey problems ! My 0-360 has started just fine from sea level to 7,000 ft . I have NOT had the opportunity to start the engine in "COLD" temps .

If someone would like the Vans electric primer solenoid with copper primer lines (AN fittings attached) send me $40.00 + shipping and it is yours . The solenoid probably has 50 hours on it . I think the Vans solenoid now goes for about $100.00 ? If you fly out to KSEE you can have it for free as long as you buy me and John Kerr lunch at the airport café ! BOOM !
RB

Higher and Faster

I'm a good KISSer...I had a primer on my current plane for the first year, then I fixed a leak, and later somehow got air in the system......PITA says I - out came the primer system - life is good - I am confident that at 0 degrees F I could engage the starter VERY shortly after 2 pumps of the throttle and 2-3 blades later she starts. Of course, I always liberally pre-heat below 40 anyway. I have a carb'd O-320
My first T-18 did not have a primer either - never a start issue in the cold - I'm in Salt Lake Utah....we have brass monkeys here, and I've had to dig a well.
If I were building, I don't think I would bother with one.

_________________
Fraser MacPhee
N926WM
Serial #279-1
Angel Fire, NM (KAXX)

"Brass Monkeys ?" You must have had a tour of the USS Constitution in Boston . The Active Duty Sailors on board gave a detail description of how the "Brass Monkeys" came to be . If you haven't had a tour of this ship , you need to put it on your bucket list .

RB

Higher and Faster

Remember Pearl Harbor

'Feisty' has a standard manual syringe primer, which feeds 3 cylinders. The right rear cylinder is tapped for manifold pressure to the panel gauge and the P-mag.
It starts right up on a blade or two, even when it's plenty frosty.
My wife has an RV-4 with VANs electric primer. It's plumbed to the back two cylinders, but feeds directly to the right one, then around the front of the engine to the rear one on the left side.
It starts kinda funny, real rich on one, ok on the other, and lean on the front two. Then it settles in to that sweet Lycoming sound.
Funny, but it used to prime only one cylinder. The second primer nozzle was clogged with solder! It never worked right from day 1!
It really chugged on one cylinder for a bit before the rest kicked in. That RV-4 shook like a wet dog on that wiggly RV landing gear until the other cylinders joined hands and got to work.
Rich, you must live in a warm place, or the primer nozzle is too big! It takes 5 seconds or more on the VANs electric primer to start Marilyn's O-320.

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE

MG,
Try this. Go mixture full rich, pump the throttle twice, full in to full out, go do the preflight, get in and crank. It should fire right up.
I had a primer on the Tigress and removed it for all the reasons stated.
Cubes

Old Piper Cub trick:

Fuel on, pump throttle twice, flip prop with mags cold about 10 blades backwards. The engine is now primed and ready to fire. Simple and cheap.

Chuck N25002

I bought the Vans electric primer as a 'kit ." It came with the solenoid , lines and "nozzles ." Warm climate ? 30 degrees at my house tonite ! 20 miles due East of KSAN . Time to put long pants on to BBQ !

RB

Higher and Faster

Same here Cubes, 2- strokes of the throttle, I pull the throttle full aft, this chokes it, second blade it lights up. That throttle plate in the carb will act as a choke plate when pulled back to Idle. ..Dan

Seems like everyone's got their own way... I'm with Fraser. My 0-320 starts in 1 or 2 blades also, and I also pre-heat below about 40 or 50 deg. It gets pretty cold around here too. Mixture full-rich, 2 full strokes of the throttle and immediately crank it over. Just one full stroke if I've already flown it that day & killed it with the mixture. My theory is that if you start cranking right away it's better, for a couple of reasons. First - the accelerator pump shoots a slightly atomized stream into the throat, and it seems to work better for me if I suck that into the engine right away before some of it settles back down & out of the carburetor (I think it can form a small pool in the bottom of the air-box). Secondly, if the engine were to back-fire, I don't want that "small pool" igniting outside of the carburetor.

_________________
John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

For the ole 320 2- strokes seems to be key here. I have used 3 in the past but that will be on the verge of flooding I have found out. We went for a spin yesterday to see the snow pack or what there is of one anyway. It was 48 deg at about 1 in the afternoon, Ira and myself were on the ground for about 15 min trying to get some heat under the cowls and it was difficult. At 8500 ft it was 26 deg, no heat in the oil time to block off the cooler, couldn't generate enough heat in the muff for good cabin heat, it was luke warm at best and the cylinder heads were below 200. Me feets froze up, me stick hand froze to the stick I thought I was going to freeze up me self. I think us flyers here in Calif set up for the 105 deg days and 122 deg on the tarmack, when a good cold front comes through it make us shiver a bit, or at least me any way, by golly it was cold you guys in the colder area of the country must be perty hardy, hats off to ya!! The old 320 does like that cold air though, it makes a serious difference in the way it runs. Would have to set up totally different if it was this way often, probably block off at least half to 2-3rds the air intakes....Dan

Good posts on primers and cold wx op's guys. Thanks. Reading previous posts I decided to use throttle-only like some of you. I put a 1/8" drain tube at bottom of my air box to prevent puddling, just in case, and that's my suggestion to anyone building new. Presently working on oil cooler install with controllable door, and got to wondering about getting enough heat into the cabin too. Heat muff will be coming up next, but it's so cold in the shop just working on it gets difficult. We're expecting about zero tonight, so we probably won't have any temperature left!

Les Krumel,
Albuquerque (@7,000 MSL)