hesitation when underway or out of gear

[Seaspot]

Hey all, I'm having a hesitation problem with my A4.

It seems to be starting ok, but it is starting a tad harder this year than last. But, after it starts, it idles fine, but when it runs at lower rpm's it has a slight hesitation. It does this on it's own. It seems to be running fine, then it starts to hessitate, kinda like it's getting bogged down a little, then after a minute or so it goes back to running good, then it does it again.

For info, I have switched over to electronic distributor, so no points or condensor to worry about, I have the flame thrower coil, electric fuel pump, new plugs, wires, bypass loop, new alternator, single action T-stat kit, new starter, new fuel tank, new fuel lines, just changed the fuel filter, new water/fuel seperator, all bought from Moyer other than the lines and filters.

It was running great, with all this new gear. Then all of a sudden I have this hesitation issue.

Any ideas? I'm maybe thinking it could be a clogged jet in the carb? Other than that I'm kinda at a loss.

[ndutton]

Seaspot,

What size is your alternator?

[Seaspot]

What sixe is the alternator? Hmmmm, I see where your going with this, I think.

But to answer you , I think it's a 65 amp.

[ndutton]

. . . . . but when it runs at lower rpm's it has a slight hesitation. It does this on it's own. It seems to be running fine, then it starts to hessitate, kinda like it's getting bogged down a little, then after a minute or so it goes back to running good, then it does it again.

This is by no means conclusive, just what popped into my head when I read your original post.

Do you have an isolated engine starting battery? If so, does this symptom persist when running only on this isolated battery? Are there longer intervals between hesitations the longer you run?

[Seaspot]

It does it no matter what battery bank i run it off of.

To me, it sounds like a fuel issue, but I'm really not sure.

It will run smooth, then it starts to hesitate. If I give it throttle at the point of hesitation, it continues to hessitate (it even gets slightly worse), then it jumps to the higher throttle setting.

It seems to hessitate at different times and at varrying degrees of hesitation, sometime worse than others. A couple times I thought it was going to cut off, but it would start to come back up in rpm's even though it was still hesitating.

[ndutton]

Yeah, I get it. Agree that it's probably not alternator load causing this. I wanted to eliminate it before you started digging into things.
Have you tried feathering the choke during one of these episodes?

[Seaspot]

No, I have never touched the choke during one of the episodes. Very good idea.

[Dave Neptune]

Hesitaition

If your hesitation is somewhat consistant you can unplug the alternator and give it another try. If the hesitation goes away you may have found the culprit and if not you have elimenated one possibility.
I doubt it is the alternator as it should just put a power drain on the engine and not cause a hesiitation. I would first suspect that one or both of the idle ports could be kruding up. However that senario should be a bit of a consistant one not intermitant. How far off the seat is the idle screw? It could be just a simple matter of the mix being on the lean side as it keeps "coming back" to normal(?). If it were to rich it should get progressively worse and foul the plugs. Try the above mentioned choke trick and do so by slowly moving the choke.

Dave Neptune

[Blue Eyes]

Fuel contamination

Could fuel contamination cause these failures?
Would filters with higher micron levels be a possible solution?
Some filters are at the 50 micron level.

[Seaspot]

I will try feathering the choke to see if that helps.

I'm not sure how far off the seat the idle screw is. The carb side of the engine is difficult to get to and since this is a new issue, I must admit that I haven't even checked it yet.

I don't think it's contaminated fuel. I thought that this might be the issue at first, so I drained the last couple gallons out of the tank, and refilled with fresh gas with some Sta-Bil in it. I also replaced the water/fuel seperator filter and replaced the inline filter.

[hanleyclifford]

It is very important that you gain access to your idle adjustment screw. If it would help, it is possible to buy a replacement screw from the catalogue on this site which can be turned by fingers alone. You may be running a little lean and turning the screw in (clockwise) 1/2 turn could give you just the little extra juice you need to get off idle smoothly.

[hanleyclifford]

You should also determine if you have an adjustable main jet or not. If you do, try enriching a little (one half turn counterclockwise).