C-90-8 Starting Method

[irishj3seaplane]

Hey guys,

Been lurking for months but would really appreciate some advice now. Modified my stock J3 with:

Zerotimed C-90-8
New Slick Mags
New McCauley Seaplane prop
Wing Tank
ATR-600 Radio
Kosala Belts
Atlee Tie Downs
Overhauled EDO 1320's - to be installed this week

The plane really hauls now. I cannot believe the takeoff performance, 80m roll fully loaded, just crazy.

I have no problem starting it cold. I give it 3 shots of prime, 6 blades and swing with throttle closed and carb heat cold. It goes first swing. But when hot it takes a bit more tweaking, and I find I need to prime it again to get her going. I have 25hrs on the engine and am running a 50/50 Mo/Av mix.

Can someone in the know tell us the best prcedure for starting, and especially now as I'll be on my own on the lake, standing on a float with lotsa people looking!!!

Help appreciated.

William Flood
Ireland

[JP]

I do hot starts simply by flipping with the throttle cracked to catch. It floods easily when hot. Then you gotta swing the prop the other way with the mags off and the throttle open to get rid of the excess fuel.

I disconnected my prime. My MS carb has the accelerator pump. Cold start is 8 blades and throttle forward, then back.

[behindpropellers]

William:

Hot Starts:

0300 Cont. 1 shot of prime when it is hot, always starts.

C90 Cont. No prime, one or two trys to start, if it does not start then, 1 shot of prime and it always starts.

It is always easier to try with less prime, rather than try starting it flooded.

[mvivion]

Its' been a while since I operated a J-3 with a C-90, but the previous two notes are almost exactly what I recall. I do recall a few hot start attempts when I managed to flood the engine (they are VERY sensitive to flooding, with just a little throttle movement), where I cranked, and cranked, etc. If that happens, mixture to idle cutoff, throttle wide open, mags off, throw it through again and again to clear it out, then just crack the throttle maybe a 1/2 inch, and start it.

MTV

[kase]

I flew a PA11-90-8F for 2000 hours and hot start for that engine was crack the throttle 1/2" to 1" . Always started it standing by the door. If it puttered once or twice ( usually because thr throttle wasnt opened up enough) and then died you had to start over by tuning it over backwards with the throttle wide open for 10 turns and start over.

[Alex Clark]

I stand on the float with my left hand on the door frame.
For cold start two or three shots of primer, four pulls through on the prop, then mags to both and one good fast flip on the prop and she starts every time.

While hot, she will flood easy. So either I just go to hot mags and start flipping the prop through. Which may work....if she feels like it...


Or, I give her one throttle boost about 3/4 to max in a fast push and pull manner. Then leave her open at three quarters of an inch throttle.
If she starts now she will really roar to life. So either have her tied up real well, or at least have the mix pulled out so she will only run for a few seconds. (if solo) That way if you fall off the float, you won't have to swim as far.

Lately I have been killing the mags just before she dies from fuel starvation with the mix pulled out. Especially if I know I am going to start her again in a few minutes. That seems to leave a little fuel load in the cylinders and she starts better hot with no primer and just pulling her through with hot mags.

If she is heading to the beach for the night or at least a few hours, then I let her engine stop through having the mixture pulled out alone.

[irishj3seaplane]

Guys,

That advice seems sound. The common theme on the hot start is little prime, if at all, and crack the throttle. I've gotten into a habbit of starting at idle at all times. I guess I'll have to be real careful trying this on floats. I had the mixture wirelocked rich, but I'll undo this as a safety measure.

Glad to hear such a positive response. Much appreciated.

[bob turner]

Check your carb - is it a Stromberg? If so, pumping the throttle does nothing if the engine is not running. If the engine is hot, a well-set up Stromberg starts on the first or second blade, with the throttle off the idle stop. If cold, the engine starts on the sixth blade, with the throttle hard against the idle stop. If really cold - I dunno; it never gets below 50 degrees here.

[rcsimpson]

I have the whole "hot start" procedure on video tape(with cursing from Alex and all). It was a standard Murphy moment right before my checkride. I blindly followed my checklist and gave it two shots of priming. Although I thought after my hour long oral exam it would have cooled down a bit. I think you had to pull it backwards at least 6-8 times to UNDO what I did. I'm a bonehead . . . .

I stand on the float with my left hand on the door frame.
For cold start two or three shots of primer, four pulls through on the prop, then mags to both and one good fast flip on the prop and she starts every time.

While hot, she will flood easy. So either I just go to hot mags and start flipping the prop through. Which may work....if she feels like it...


Or, I give her one throttle boost about 3/4 to max in a fast push and pull manner. Then leave her open at three quarters of an inch throttle.
If she starts now she will really roar to life. So either have her tied up real well, or at least have the mix pulled out so she will only run for a few seconds. (if solo) That way if you fall off the float, you won't have to swim as far.

Lately I have been killing the mags just before she dies from fuel starvation with the mix pulled out. Especially if I know I am going to start her again in a few minutes. That seems to leave a little fuel load in the cylinders and she starts better hot with no primer and just pulling her through with hot mags.

If she is heading to the beach for the night or at least a few hours, then I let her engine stop through having the mixture pulled out alone.

[Alex Clark]

You-know-who, did the same thing after you on the next check ride. By then I was getting pretty good at clearing the fuel out of the cylinders. The throttle pump method worked better in that case.

You sure would have thought that she would have been cooled off but I guess not. Plus we killed the mags when pulling up to the dock. So there must have already been a good fuel load in the system.

That sure was a warm day. Good thing the DPE had a shaded porch swing for me to sit in while waiting.

[rcsimpson]

Based on the video I saw there wasn't alot of sitting going on. It looked like you were pacing back and forth, biting the nails, etc. I didn't realize that was the first time you'd seen your "baby" take off without you in it. A traumatizing experience for sure, knowing that a Texas flatlander was at the controls . . . .

My favorite part of the tape is right after I cast off when you said, "You break it, you buy it!" A great way to start a checkride . . . .

You-know-who, did the same thing after you on the next check ride. By then I was getting pretty good at clearing the fuel out of the cylinders. The throttle pump method worked better in that case.

You sure would have thought that she would have been cooled off but I guess not. Plus we killed the mags when pulling up to the dock. So there must have already been a good fuel load in the system.

That sure was a warm day. Good thing the DPE had a shaded porch swing for me to sit in while waiting.

[aktango58]

my champ had a c-90. Had trouble for a while on the hot start.

First and most important think I learned was to tie the tail to something that would hold it from going away....

Once had the person in the back seat hold the throttle, and "pull it back when she starts"..... about saw the plane go over the edge then.

So, I tie it.

When hot starting I also kill the engine with the mags. Turn the mags back on, one blade and she comes to life. If I kill it with mixture, lots of blue smoke.

[garyh]

ak,
do you pull the mixture after turning off mags or just leave it rich?
thanks,

gary

[cubdriver2]

It's a simple engine, put your hand on a front cylinder and if you feel any heat at all just crack the throttle 1/8" and go hot and most will start on first blade, if it doesn't start by 3rd blade it needs a small shot of prime. I always shut down by turning mags off, when your on floats you don't have time to wait for it to quit with the mixture.

Glenn

Glenn

[Bill Rusk]

If I may offer a suggestion.....

Never hand prop a airplane with the throttle more than just a tiny bit cracked. If you open the throttle to flip the engine backwards to clear a flooded condition, don't forget to put the throttle back to idle. Every year folks are hurt and airplanes are destroyed when airplanes are hand propped with the throttle open, they then run wild, careen across the ramp and into other people or planes. Happens all the time. If the engine will not start in idle, get it fixed. Personally I will not hand prop any engine in other than idle, regardless of who is at the controls.

Just my opinion, having read this same story way too many times. The C-90 is a great engine and you have a great combination. Good luck. I think you are really going to enjoy that airplane.

Bill

[Clyde Barker]

I agree with Bill Rusk about starting only with the throttle closed. If your's won't do it get the carb set up right and it will.

My experimental Cub has an 0-200 that's been converted to a -8, so I have to hand prop to start. It has a C90 cam, so it is pretty much the same as a C-90-8. It also has a Marvel carb. I do not have a primer installed.

Cold and mags off, I pump the throttle open and closed twice and then pull through 7 blades. It will start at idle first pull if the OAT is above 60° F or so. If it is colder than that it will need another pump of the throttle and about 5 more blades pulled through. It almost always starts on the first pull with the throttle at idle.

If I know I'm going to do a hot re-start right after shutdown, I just shut it down with the mags. It's not a bad idea to do this every so often anyway to make sure the p leads are grounded. Just leave the throttle closed and it will usually go the first pull. If I shut it down with the mixture and then have to do a hot start it likes one pump of the throttle, pull through 5 blades and then it is ready to start, again at throttle closed.

They all seem to be a little different, but with some experimentation you'll find the right combination for your plane.

[mongo]

My O360 I pump the throttle 4 times when cold 6 if below freezing and it will always start on the 2nd blade.
I kill it with mixture and use one pump when hot, usually starts 3rd blade, if not one more pump then she will catch.
I only have one impulse mag as a side note.

Sent from my HTC Evo using Tapatalk

[Douten]

Mine is 2 shots prime when cold 2nd or 3rd blade will fire shut down with mags, if warm at all first blade and if not by 3 prime 1 shot and shut off fuel or it will flood most times when it kicks, throttle closed or just cracked. great engine and they all have their own attitude.

[Carey Gray]

I've always started my O-320 at idle cut-off. That gives you just a couple seconds to get your poop in a group and richen the mixture, or the engine dies. So, if you don't really have the throttle where you want it (closed), the airplane doesn't leave without you.
If you don't have idle cut-off, nevermind.

[L18C-95]

Interesting comment on C90 8F being shut down using mixture ICO - I had always understood that while you can have a mixture control (mine is there in theory to visit France/Italy which would require leaning for density altitude reasons), it is not set up for ICO, hence the SOP is to shut down with mags off. Mine, in fact cannot ICO.

I should know this, but two starting related questions - would the standard PA18-95 set up have impulse couplings on both mags, and would a carburetor accelerator pump be installed?

[cubdriver2]

Interesting comment on C90 8F being shut down using mixture ICO - I had always understood that while you can have a mixture control (mine is there in theory to visit France/Italy which would require leaning for density altitude reasons), it is not set up for ICO, hence the SOP is to shut down with mags off. Mine, in fact cannot ICO.

I should know this, but two starting related questions - would the standard PA18-95 set up have impulse couplings on both mags, and would a carburetor accelerator pump be installed?

Most have 2 impulse, you could check next time you have the plug wires off and turn it over really really slow and if you hear two snaps you have two impulse. Or try starting on L or R alone and you'll feel it try to kick back if mag doesn't have an impulse. If you have a Marvel Schebler you have a accelerator pump, but by your description of the mixture not killing the engine it sounds like you have a Stromberg and it does not have a acc pump.

Glenn

[L18C-95]

Glenn many thanks - based on input found on the forum and what I am comfortable with my SOP is:

Tail tie down (will investigate a Schweizer tug cable as I have a Maule TW)
Chocs
Mags off
Throttle closed
Fuel on
If cold one shot of prime
Pull through treating prop as live - I hand prop from the front, have not got comfortable with handpropping from the rear probably because need to be briefed
Mixture lean
Fuel off
Throttle hardly cracked
Mags on
Start
Walk round the wing behind struts to set idle and fuel on
Untie, unchock (I like the small chock suggestion after start)

If not starting when warm will let it rest to avoid flooding and have a cup of tea and come back after 15 minutes

The C90 8F seems to start easily when cold, occasionally temperamental when warm, but slow patience seems to work

Would add that in addition to always treating the prop as live I walk around the propeller arc when the engine is shut down, .... more so when engine is on!

[cubdriver2]

Keep doing what ever works for you. But if you do have a Stromberg and it's above 40F and the engine is cold try this, don't prime and throttle totally closed, Stromberg has idle circut when throttle is totally closed and will suck up fuel and start. If you have been flying and engine has any heat at all ( put hand on cylinder before starting ) try just cracking throttle an 1/8" to get it off of the idle curcut ( remember it sucks fuel and will flood on the idle circut when hot ) and then turn mag on and most times it will start first blade.

Glenn

[airwolf7ac]

I found when shutting down for a short period of time I use the mags, if for the night the mixture. If it doesn't start hot on first flick with throttle cracked, .5 shot of prime and usually goes. This is on floats, winter on skis can be tricky.

[Skip]

I had a C-85 with 0-200 crank rods and pistons and I never had to use the primer to start it hot. Just crack the throttle and it always starte on the first blade.