O360 starting problem

I have a new Lyc O 360, LASER ignition, Facet fuel pump. Most times it start within a few blades, but twice, recently I just can not get it started. I generally turn on the pump, pump the throttle 3 times, turn off the pump and hit the starter. Works most times but not today with CFII in the right seat. We could smell gas in the air inlet. LASER fuse was OK.

I'll appreciate any suggestions on better procedures.

Roy Samuelson

Pumping the throttle while engine isn't cranking dumps fuel right down into the airbox where it pools as liquid. Might be better to crank while pumping.

hard starting

Roy, I would leave the pump on until the engine starts(unlike fuel injection). Also, you might need 4 or 5 pumps on the throttle if the temps are below 45- 50 degreesto get it to fire. Closer to freezing, you might consider a primer(Vans sells a kit) which works well, on two cyls. Then you don't need to pump the throttle.

First start

It was the first start of the day. Cool temps, maybe in the 50's.

Roy

O360 starting

I use to start the way you said that you do. Then someone told me to try this. (Carb not injected)

I turn on the fuel pump until the pressure is between 4.5 - 5.0 then turn it off.
I pump the throttle 1 time then close the throttle completely. Immediately start the engine. As soon as it starts advance the throttle and adjust to 800 rpms. It normally starts within a couple blades.

I have been starting this way ever since and have not had any problems. One pump of the throttle then Closing the throttle all the way before starting works great for me. When I first heard of this way of starting, I did not think that it would work very good, I almost didn't even try it. I'm glad I did!

Sometimes my hot starts take a little longer, but not much.

A little scary!

I know that there are as many ways to start engines as their are pilots, mechanics, and engines - combined....but there is one thing that scares me when I read it, and that is "pumping the throttle, then cranking the engine..." With our updraft carbs, all you do when you pump the throttle (and squirt out fuel with the accelerator pump) without that big air pump (the engine) sucking it up is dump raw fuel into th bottom of your air box. Your fiberglass air box. Enclosed in your fiberglass cowl. Flammable fiberglass. Need I say more? Be safe - with a metal air box and metal cowl ala most of the Spam cans people learned to fly in, a backfire into fuel is not always catastrophic (but can be) - in an RV, I would be much more worried!

I prime with my throttle, but I ONLY do it when the engine is cranking. I also don't see the value (with a carb'ed engine of course) of turning off the fuel pump once you have turned it on. The float valve in the carburetor is a valve that shuts off the flow of fuel once the bowl is full - the pump doesn't keep dumping gas, unless the valve is malfunctioning, and then the carb doesn't really work anyway. Turning the pump on for a few seconds then off is perfectly normal procedure for an injected engine, and I think people are being taught that by rote from folks who might be thinking about the machine they are operating.

(Sorry if that sounds like a rant....My problem is that I'm an engineer, and think about how the machine works, what it needs, and how it's going to react....)

Of course, when all else fails, there is the Lycoming operators manual...and no, I don't use that procedure all the time either....you see, if you hold your mouth just so, and ...

Paul

Cooler - let the fuel sit a longer

I assume you have no primer. Might I suggest you pump the throttle once or twice than wait. When temps drop it takes longer for the gasoline to vaporize. Waiting a little longer from the time you pump prime and start will help (like a minute). Prime earlier during your preflight and than finish preflight while the gasoline gases off.

If you want just right before you start give it an extra pump. Than throttle cranked open and start, or as Ironflight said, pump the throttle while cranking, which is what I mostly do. Still if cold I give it a "pre-pump" or two.

Be sure to go back to throttle cracked or slightly open after you pump during cranking. If the throttle is open too much than it might not fire. Throttle open too much will kill the engine. Of course closed is not going to work either. You have to get the right fuel/air mix. Throttle open too much will kill the engine. Oh yes, hold your mouth just right.

Of course preheating the oil is a good thing since that heats the sump/plenum and not only helps with lubrication but starting, since fuel will vaporize faster.

I hear Ironflight and can't disagree with cation, but usually one or two shots is not going to burn your plane down. Next time you have the cowl off have someone pump the throttle and watch. Chances are the fuel will not be enough to puddle, but if it does it will puddle along the edge of the filter and not go anywhere. This is of course one or two pumps, 3 or more you are going to have puddling.

My carbed 0-360 engine has started so well (first revolution) with Van's three cylinder priming system, that a friend re-installed a primer setup after initially removing it. (Note: when he got his engine, primer ports were installed)

L.Adamson -- RV6A

gmcjetpilot said:

I assume you have no primer. Might I suggest you pump the throttle once or twice than wait. When temps drop it takes longer for the gasoline to vaporize. Waiting a little longer from the time you pump prime and start will help (like a minute). Prime earlier during your preflight and than finish preflight while the gasoline gases off.

Click to expand...

I could not disagree more. Two pumps and then letting it sit will produce a nice puddle on the ground since all the fuel runs into the airbox and out the drain holes, down the gearleg (A models) and makes a mess of the wheelpant to boot.

Next time you have a M4-5 laying on the bench full of fuel, take it out on the ramp and pump the throttle lever once. Make sure your out of the way as it can squirt fuel 10 feet in the air. **** like a horse it does.

I have a priming system on my 6A and have started both ways; with the primer or using the throttle. It takes two to three pumps of the throttle before start and never starts as easy as with my 4 port primer. So, I am a true believer in engine primers.

As GmcJetpilot states; after each stroke of the throttle and back, the throttle must be cracked 1/4 to 1/2" after each stroke to allow air in with the fuel the engine just sucked up.

Well I agree

zilik said:

I could not disagree more. Two pumps and then letting it sit will produce a nice puddle on the ground since all the fuel runs into the airbox and out the drain holes, down the gearleg (A models) and makes a mess of the wheelpant to boot.

Click to expand...

The drain hole is out side the filter area, yes my friend. The filter seals pretty well. As far as all the mess you describe going down gear legs and wheel pants, WOW! That sounds funny and scary. If that's happening than I would say don't throttle prime. I do think people over do it. My airbox did not leak and I had a little hole on the back bottom (but out side the filter area).

Next time you have a M4-5 laying on the bench full of fuel, take it out on the ramp and pump the throttle lever once. Make sure your out of the way as it can squirt fuel 10 feet in the air. **** like a horse it does.

Click to expand...

I have seen it; it's a squirtgun, but its not that much fuel. If you don't like to prime with the throttle and accelerator pump I'm not going to criticize, it's a work around. As Ironflight says and pump-prime only while cranking.

I have a priming system on my 6A and have started both ways; with the primer or using the throttle. It takes two to three pumps of the throttle before start and never starts as easy as with my 4 port primer. So, I am a true believer in engine primers.

Click to expand...

That is a way to go, a good way, but some live in very temperate climates and the weight (and cost) savings is pretty nice. It's experimental and its a choice. I've never had an issue starting O360's down to 45-50F w/o primer. I've had the primer as well and liked it.

As GmcJetpilot states; after each stroke of the throttle and back, the throttle must be cracked 1/4 to 1/2" after each stroke to allow air in with the fuel the engine just sucked up.

Click to expand...

Roger roger.

O360 starting

I start my engine with the throttle completely closed all the time. See my previous post for my starting procedure. It works great on my engine

gmcjetpilot said:

Be sure to go back to throttle cracked or slightly open after you pump during cranking. If the throttle is open too much than it might not fire. Throttle open too much will kill the engine. Of course closed is not going to work either. You have to get the right fuel/air mix. Throttle open too much will kill the engine. Oh yes, hold your mouth just right.

Click to expand...

gmcjetpilot said:

The drain hole is out side the filter area, yes my friend. The filter seals pretty well. SNIP

Click to expand...

I certainly could be wrong, but I believe it to be good practice to have drain holes both inside and outside the filter. I have a hole inside the filter, which I drain with a small fitting prosealed to the outside of the FAB (don't put anything which could come loose inboard of the filter!). This is connected to a small hose which runs slobber out the cooling air exit. I'd much rather have excess fuel dumped on the ground than inside the cowl.

RS,
Had LASAR on my Arrow for more than 900 hrs and never a hard start, as does my RV10. But since you are carburated, starting after pumping rather than priming is dangerous. Our carbs are of the worst design, updraft. Pumping fuel will only create a pool of raw gas. True, suction will "create" a flamable mixture, but it will be much too lean and an invitation for a backfire. The added raw gas will also feed the flame. Use a primer, and your starting cold will be vastly improve and far safer.
TT
RV10 N968TP

Primer.

So, how many seconds do you keep the primer pump going. This has always been a question in my mind. I have a 3 line system.

Deke

I guess this is kind of turning into a starting procedure thread as opposed to helping fix one person's configuration and procedure. I'll feed the fire:
I have a Mattituck O320 with full primer. I prime for 3-4sec on each and every cold start. No matter if it is 40 or 100 deg OAT. I crack the throttle just a hair (less than 1/4") and it lights almost immediately every time. That is my cold start. My hot start is totally different. I don't prime, don't turn on the pump, and I keep the throttle full closed. I hit the button and it fires very quickly and I advance the throttle a little to bring the idle up. I guess they're all different.
It took me quite some time to figure out not to mess with it when it is hot and to just hit the starter. Oh, and I do position my toung just right for good measure. That is one of the things I love about my Lycoming, it has its own personality that responds equally well to highly engineered procedures and the ocasional waiving of dead chickens .

H i Roy,
My RV-6 had a O-360A1A with Lasar and I had starting issues the first few months. What I found out was that the lasar unit has a self perservation circuit that kicks in around 7-8 vdc and my battery was old enough that the skytec starter pulled it down to that range and she wouldn't start. If I pulled the lasar breaker and then hit the starter for a few blades and push the breaker in she fired right up. With a new battery no issues till the battery degraded then back to cycling the breaker.Unison has what called "bush kit" that put an impulse coupler in a mag. I loved the lasar once I got it figured out.

John Hughes
So Cal
N164JH "SOLD"

LASAR O-360-A1A, 3 cylinder prime

LASAR O-360-A1A, 3 cylinder priming:

Warm temperature cold start: aux. fuel pump on, throttle to run position, activate primer solenoid for 5 seconds, deactivate primer solenoid, switch on for start. If it doesn't start within 1 second (seldom ever) switch off, re-prime and try again.

Colder temperature cold start: aux. fuel pump on, throttle to run position, activate primer solenoid for 5 seconds, deactivate primer solenoid, switch on for start. If it doesn't start within 1 second (occasionally) switch off, re-prime for 6 seconds and try again.

Hot start: aux. fuel pump on, throttle to run position, switch on for start. If it doesn't start within 1 second (maybe 1 time in 4 years) switch off, prime for 3 seconds and try again.

Bob Axsom

Just a side note........Unison just published new prices for all LASAR components. They went up a lot..... in most cases as much as 300-400 percent. A controller that used to list for around 900.00-1000.00 now runs 4400.00. Mags went up a lot too!
Don't know the reason for the large increases, but we double checked to make sure they were real, and they are.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."

Update - March 2008

I continue to have starting problems even after trying many different 'priming' schemes. Latest theory is that the problem is with the LASAR ignition.

Turns out that the LASAR needs to be in it's 'automatic' mode to start. I had installed the optional indicator light but have not watched it during the start. With power on, it goes to 'backup' mode but should go to 'automatic' within 2-3 blades and this is what happened on the last, successful start (when I did watch the light).

It may not go 'automatic' if it sees a spike drop in voltage as when you hit the starter. If it does not start in 2-3 blades, fix is to stop cranking, recycle the power to the LASAR to clear the fault, and try again.

Another fix is to keep the LASAR turned off until a few blades have passed (thus avoiding the spike) then turn it on. I don't have a pullable CB but intend to put a on-off switch in the circuit.

I have not tried any of this as I am out-of-town but will try this weekend. The above info came from several emails with Unison which responded often within the hour. I was impressed with this level of customer service.

Pullable Circuit Breaker

I have a pullable circuit breaker for LASAR power. I installed it per Unison's support engineer's direction as I worked through the initial problem caused by Lycoming incorrect timing. Recently I had a cold weather start situation with a marginal battery. I had read the post in this thread about pulling the circuit breaker center shaft to the "off" position and pushing it in after the engine is turning over and is a lower load on the battery. It seemed like a logical approach to the situation as I know the LASAR system will not start using the normal procedure if the battery power is low and if it doesn't start on the second try I'm in for a long battery charge. In this case I still had sufficient power to turn the engine over but not start it running. I tried the suggested procedure with the circuit breaker "off" to start cranking and "on" while cranking to start running and it worked very well on the first attempt.

I think this control implementation is better than the separate switch since it provides the circuit breaker function and it is less likely to be accidently placed in the wrong position.

Bob Axsom