Hard starting PA38

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Fluffysgrandad

Filing Flight Plan
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Fluffysgrandad
Hoping for some suggestions here. My PA38 with Lycoming O235 has progressively become harder to start.
It needs up to 10 primes from cold and even needs a prime now when warm. The impulse coupling was changed a while back for a different reason and doesn't appear to be the issue.
I am wondering about air leaks in the primer or carby. Not sure if I am on the right track here. Thanks
 
Fluffysgrandad said:
Hoping for some suggestions here. My PA38 with Lycoming O235 has progressively become harder to start.
It needs up to 10 primes from cold and even needs a prime now when warm. The impulse coupling was changed a while back for a different reason and doesn't appear to be the issue.
I am wondering about air leaks in the primer or carby. Not sure if I am on the right track here. Thanks
Click to expand...

235s were famously hard to start. Many had two impulse mags to alleviate it.

The primer nozzles get gummed up with the residue from boiled-off fuel. They start squirting it in a stream instead of a finely atomized spray. The stream does little good. You might have those checked to see what they're up to.

And the sparkplugs. If they're Champs they might have high resistances. Been seeing way too much of that, which is probably why they changed their plug design recently. If you get new plugs, get Tempest UREM37BY (or the new, updated Champ REM37BY, if you must have Champs) and it will start better. They are resistant to fouling, another bad O-235 habit.

Dan
 
Might check the magneto points and cap good for about 1000hr, famous for making it hard to start.
 
Fluffysgrandad said:
Hoping for some suggestions here. My PA38 with Lycoming O235 has progressively become harder to start.
It needs up to 10 primes from cold and even needs a prime now when warm. The impulse coupling was changed a while back for a different reason and doesn't appear to be the issue.
I am wondering about air leaks in the primer or carby. Not sure if I am on the right track here. Thanks
Click to expand...

Try and think... this ain't brain surgery, take it to a A&P and get it fixed.
 
Thanks for the replies. My mechanic is out of the country at the moment and I am a long way from another one. Just looking for some advice as to whether it's an immediate safety issue or not. Thanks
 
Does the 235 carb have an accelerator pump ? See if you can prime it with the throttle.
 
weilke said:
Does the 235 carb have an accelerator pump ? See if you can prime it with the throttle.
Click to expand...

Just make sure the engine is spinning before you pump the throttle; otherwise the fuel runs down in the air box and out the corners and has a propensity to burn planes to a crisp.
 
The carb on a Tomahawk does not have an accelerator pump.

One of the problems with that engine is that the plugs lead foul on a routine basis. I'd start by pulling and cleaning the plugs.
 
It depends on the model of O-235 as to whether it has an accelerator pump. Many don't. The Citabria 7ECA doesn't have it. O-235L2C.
 
kyleb said:
One of the problems with that engine is that the plugs lead foul on a routine basis. I'd start by pulling and cleaning the plugs.
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That's what the REM37BY plugs are for. They can't foul up like deep-well plugs.

ae363421-2cdf-4709-afc0-3e09526bb28a.jpg


Dan
 
Dan Thomas said:
That's what the REM37BY plugs are for. They can't foul up like deep-well plugs.

ae363421-2cdf-4709-afc0-3e09526bb28a.jpg


Dan
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I wouldn't buy the Champion version though since there's no way to tell if you have an old set with the crap resistors or the new ones they came out with recently to deal with the aforementioned problems.
 
Dan Thomas said:
It depends on the model of O-235 as to whether it has an accelerator pump. Many don't. The Citabria 7ECA doesn't have it. O-235L2C.
Click to expand...

Here is the TCDS for the-L2C. Show me the alternate carb?

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/0a059b37ac25df6786257b63006b66b9/$FILE/E-223_Rev_21.pdf
 
Henning said:
I wouldn't buy the Champion version though since there's no way to tell if you have an old set with the crap resistors or the new ones they came out with recently to deal with the aforementioned problems.
Click to expand...

If you look down the well you can see the slotted screw head on the old style terminal. The new one has no slot in the terminal.

But of course, you have to take them out of the package to do that, and I don't imagine too many sellers are going to let you cut the plastic sleeves open.
 
Tom-D said:
Here is the TCDS for the-L2C. Show me the alternate carb?

http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/0a059b37ac25df6786257b63006b66b9/$FILE/E-223_Rev_21.pdf
Click to expand...


MAde a mistake in the model, I did. The engine is the -K2C, but uses the same carb as the -L2C, the MA-3A or MA-3PA.

A couple of other references identifying the carb (part number 10-5199) for the -K2C:

http://www.lycoming.com/Lycoming/PR...h_by/aircraft/value/7ECA/Default.aspx#details

and http://msacarbs.com/10-59956.html

The MA-3A is shown here:


QAA4DSC_0035.jpg



No accelerator pump.

The MA-3PA has the pump.

The Tomahawk (PA-38-112) uses the -L2C engine, using the same carb options as the -K2C.

http://www.lycoming.com/Lycoming/PR...h_by/aircraft/value/7ECA/Default.aspx#details

The "A" in MA means altitude compensating, or mixture control. The "P" means accelerator pump. I used to have a CD somewhere that gave out all this sort of hard-to-find info.

Dan
 
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Dan Thomas said:
If you look down the well you can see the slotted screw head on the old style terminal. The new one has no slot in the terminal.

But of course, you have to take them out of the package to do that, and I don't imagine too many sellers are going to let you cut the plastic sleeves open.
Click to expand...

Exactly the problem.:( Champion should have pulled the old plugs and eaten them. They've made plenty of money pawning off that junk already.
 
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