Hard starting citabria

I have a buddy of mine that has a 1996 Citabria 7ECA with a Lyc. O-235-K2C. He has owned the airplane for 8 years or more and has always had a problem starting it. He has been on the Citabria site and had them try to figure out what the problem is - with no luck. I told him that I would ask here and see if we can find the problem. Here are the particulars:

Skytec starter (this problem may have begun with the high speed of the starter)

requires 8 pumps of the primer when cold and 4 when hot to get it to fire (he has tried many different combinations over the years and this is the best) The engine only has primer lines to two of the cylinders instead of all 4

the prop turns through 10 blades until it fires (to me it seems to be over primed but he says it takes longer with less prime)

it has Slick mags with impulse couplings on both

he rebuilt the mags 7 years ago and there was no change in starting

there is no kick-back

compressions are all in the mid 70's

burns strictly 100LL and the bottom plugs foul after about 10 hours - cleaning or replacing the plugs make no difference in starting.

I asked him to try hand propping to see if it made any difference - don't know if he has done that yet

He talked with Lycoming about the problem and also the plug fouling. They didn't recommend the Iridium plugs because the engine runs so cool.
Any ideas that you have I'll pass along to him. I know that there is someone else with a Citabria and the same engine that is having the same problem. He said that he gave up about 6 years ago and is just living with the hard starting.

Thanks

Brian

Has he tried using the accelerator pump on the carburetor, or do these carbs not have an accelerator pump?

MTV

Hello Mike

He does not have the accelerator pump on this engine.

I just got an email from him regarding hand propping. He said that he recently tried to hand prop it and got it started with about 4 blades vs. 10 if he uses the starter.

Brian

sounds normal to me, especially without the excellerator pump. Usually when you prime an engine the prime must be full of fuel before it enters the engine, so 8 pump may very well be 3-4 full pump of actull raw fuel i.e 4 pumps of air then4 pumps of fuel= 8 total pumps

Hard Starting

Had the same problem with the 0-235-L2C's in the Cessna 152's and have seen it on other 7ECA's. The starter is turning the engine so fast the impulse doesn't work. My fix was to just bump the starter as it always seemed to fire after it cranked and I let off on the starter switch.
Good luck on the lead problem. I had a spare set of plugs that I rotated out every 25 hours and leaned the heck out of it all the time. (including ground time)

Josh I think that he has the "short" primer to start with so it probably does take more pumps to get the fuel to the clyinders.

d.grimm One of the first questions that I asked him was if he has tried "bumping" the starter. He has done that and it seems to make no difference. I have to assume that the impulse couplings are working since the engine does start.

Thanks

Brian

Here's what I do.

Cold , it takes more prime than you think. 3 to 4 good shots.
Dont open the throttle more than a crack , any more and it delays a good start

Hot, lets say with in an hour, same procedure. Again don't open the thottle more than a crack.

Have him try turning of the engine by the mag switch at idol and then try fire it up. If it bangs right off, he just needs to tweek his technique. If it doesnt' he might have ignition/mag troubles.

Another thing is these engines in opinion are require a good spin. A sluggesh battery or starter will make it difficult. Not an easy one to prop like a 320. Low compression hampers this I think.

citabria

carb

Anybody tried "slick start"? I have those kind of problems on my C-180. It acts like it is not firing.

sj

Jeff I'll have him try shutting down with the mags and then restart to see what if any difference he get. This guy, buy the way, is a 10,000+ hr with A&P / IA. I know that he has tried everything that he can think of and gave up about 6 years ago.

Leon I'll ask him and see if he has done anything to the carb. My memory is failing me at the moment but I think that he did overhaul the carb and have it flowed.

Steve What is Slick Start??

Thanks

Brian

http://www.aircraftspruce.com/catalog/eppages/slickstart.php

Hey, that looks pretty "Slick" (pun intended)

Brian

Sometimes one word answers are the best. "Carb" is an excellent one word answer. If idle circuits are not working well, or if butterfly doesn't fully close, no suckee. Same with incorrect float level. And just because you send them out and pay big bucks is no reason to assume anything!

I never really thought about it, but if the starter can turn the engine fast enough to bypass the impulses, that could be a problem - although the impulses are not needed anyway at higher rpm. "Carb"

Take a look at Lycoming Service Instruction 1362, it applies to L2C engines but you may have related issue. The impulse coupling lag was changed from 15 degrees to 5 degrees on L2C engines due to the speed of the starter causing hard start problems. Maybe yours is a similar problem. Jim

Cruiser: I said something to him last week about the impulse coupling lag angle but he has not had time to check into it yet.

What puzzles me in thinking about a possible carb problem or the lag angle is that he only had to pull it through 4 blades to start by hand propping. That leads me to believe that it may be the lag angle and the high speed of the starter need to be matched up. However, it would also seem that if the impulse lag angle were the problem, then he should be able to start it "bumping" the starter to get a lower starter speed. That does not seem to work either. :evil:

I appreciate all the input

Brian