Hard starting C145
Moderators: GAHorn, Karl Towle, Bruce Fenstermacher
Hard starting C145
A few years ago I overhaued my engine. When it was returned it was harder to start particularly in cold weather. It would start with the primer but would not stay running. Now I have started to have problems starting when hot. Today I had trouble with the first start on a 97 degree day. The engine will fire on one or two cylinders and almost starts but then died if you let off on the starter. No combination of mixture or throttle seemed to make a difference. The engine finally started during one of the times it was hitting on one or two and I gave it a hard shot of primer. After starting it has always run great. At overhaul time I got a rebuilt carb but because the Slick Mags were fairly new nothing was done with them. Any ideas? Bill K
Polished 48 170 Cat 22 JD 620 & Pug
How cold is cold?
Below freezing, the standard installation can be pretty tricky on an engine that has not been pre-heated. Five or even Six shots of primer, and even then I keep another primer already loaded and ready to shove in when it fires...is sometimes necessary on a really cold engine. The C145/O300 is not noted for easy starting when it's really cold.
But for it to give troubles during the summer...??? Either you're priming it (and flooding it) or there's something else going on with your carb/induction system.
At standard atmospheric (59C) and above, ...it should require no priming other than a few strokes of the throttle before cranking it for an easy start.
Below freezing, the standard installation can be pretty tricky on an engine that has not been pre-heated. Five or even Six shots of primer, and even then I keep another primer already loaded and ready to shove in when it fires...is sometimes necessary on a really cold engine. The C145/O300 is not noted for easy starting when it's really cold.
But for it to give troubles during the summer...??? Either you're priming it (and flooding it) or there's something else going on with your carb/induction system.
At standard atmospheric (59C) and above, ...it should require no priming other than a few strokes of the throttle before cranking it for an easy start.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention.
An originality nut (mostly) for the right reasons.
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zero.one.victor
- Posts: 2271
- Joined: Tue Apr 23, 2002 12:11 am
Bill, I had the same sort of problem a couple summers ago. I thought it was because I needed a new starting routine (primer/pump/etc) due to the warmer weather. Then one day my airplane just WOULD NOT start- left me stranded at another airport. Fooled with the mags,even pulled them off for troubleshooting/bench testing. They checked out fine, the mag guy asked me how many hours on the plugs? I told him about 500, he said that was the problem. I said they looked great, clean, very little erosion-- nope, he insisted it was the plugs. I bought 6 new ones from him for the bottom & it started right up. So I bought another 6 for the top.
He told me that the "R" in the REM plug number stood for resistor, and that the more times that plug sparks, the more resistance builds up in that resistor. After awhile, there's just not enough spark available to fire the plug.
A year or so after the plug episode, my engine started running rough on one mag and it turned out that a set of points & a new condensor fixed it right up. This is with only about 5-600 hours on new Slicks.
So I would guess plugs and/or mag(s).Good luck with it.
Eric
He told me that the "R" in the REM plug number stood for resistor, and that the more times that plug sparks, the more resistance builds up in that resistor. After awhile, there's just not enough spark available to fire the plug.
A year or so after the plug episode, my engine started running rough on one mag and it turned out that a set of points & a new condensor fixed it right up. This is with only about 5-600 hours on new Slicks.
So I would guess plugs and/or mag(s).Good luck with it.
Eric
If you can determine that it is fire, vs the fuel, I would add the leads to what Eric has mentioned. You could either have them checked, or borrow a harness from someone to try and see if it makes a difference.
On the fuel possiblity, since it is a recent overhaul, the intake gaskets are probably fairly new. But since it was hard to start from the beginning since overhaul, maybe they didn't do the carb right. It would be helpful if you could try another carb.
On the fuel possiblity, since it is a recent overhaul, the intake gaskets are probably fairly new. But since it was hard to start from the beginning since overhaul, maybe they didn't do the carb right. It would be helpful if you could try another carb.
Joe
51 C170A
Grand Prairie, TX
51 C170A
Grand Prairie, TX
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cessna170bdriver
- Posts: 4063
- Joined: Mon Apr 22, 2002 5:13 pm
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Jr.CubBuilder
- Posts: 517
- Joined: Thu Aug 12, 2004 10:33 pm
I just had to replace a wiring harness because of one bad wire, there was nothing visually wrong with it. I've also experienced the same sort of thing that Eric describes, but with automotive plugs. The plugs looked fine, but a couple of them had developed hairline cracks in the ceramic that weren't visable to the naked eye. I could see the sparks migrating to ground when I was working on it one night.
Another plane owner at our airport was unable to make static power with his homebuilt (T18 Lyc 320). He changed the prop, rebuilt the carb, fiddled with the intake, put on a K&N intake filter, and none of that helped (he got a few RPMs with the flatter prop but it still wasn't right). He finally changed plugs, and bingo he got another 100-150 RPMs at static. The moral is try the simple stuff like the plugs, before you go tearing the carb apart.
Another plane owner at our airport was unable to make static power with his homebuilt (T18 Lyc 320). He changed the prop, rebuilt the carb, fiddled with the intake, put on a K&N intake filter, and none of that helped (he got a few RPMs with the flatter prop but it still wasn't right). He finally changed plugs, and bingo he got another 100-150 RPMs at static. The moral is try the simple stuff like the plugs, before you go tearing the carb apart.
I think I may have found the most recent part of the problem. We removed the primer line today and the removed the nozzle. There was no small hole for the fuel to go thru and atomize. It would shoot a stream the same diameter as the primer line. So we will get the proper nozzle and keep you posted. Lets hope that solves the problem. Bill K
Polished 48 170 Cat 22 JD 620 & Pug
hard starting cold wx
I had same problem as temperatures dropped below 0 'C. Last annual a metered nozzle was installed to help atomize fuel prime. My starting was harder than ever.
I had a second nozzle installed on the opposite intake manifold, and problem was fixed. On -10' C day, 3 shots of prime, with 1 ready to shoot during initial firing, works fantastic. I always wondered why only one manifold had a primer...
I had a second nozzle installed on the opposite intake manifold, and problem was fixed. On -10' C day, 3 shots of prime, with 1 ready to shoot during initial firing, works fantastic. I always wondered why only one manifold had a primer...