Going Aisin-details, details, details

[Pin_Head]

Houston, we have idle! Cleaning up the old 65 primary slow jet and combined with manifold vacuum to the PV and TP allowed me to set an idle and adjust mixture screw. Driving it was smooth albeit with less pull across the power band as yesterday's bastardization.

So just for posterity and 11 pages of text what was the culprit? Was it the pluggd primary slow jet?

 

[77mustard40]

So just for posterity and 11 pages of text what was the culprit? Was it the pluggd primary slow jet?

Trust me I have given this thought all along the way, but remember that I began my rebuild and conversion process on a tricycle and may now have just made it to training wheels. So I'm probably as qualified as a kindergardener to point the finger of blame.

In the end I don't have the culprit under lock and key but am suspecting a bad, fowled, or under sized primary slow jet. In the 2 times I have completely disassymbled this carb looking for a problem I never thought to change or clear out the slow jets themselves (hell they were brand new). Each time I was focused on the passages in the body components themselves, thinking I must have an obstruction in there somewhere.

I have looked back at my rebuild thread https://forum.ih8mud.com/40-55-series-tech/523785-another-carb-rebuild-thread.html and found a number of major problems with the state of the core: Power piston impropery retained, both slow jets completely restricted, secondary main jet mangled from prior removal attempts. I know that I corrected items one and three, and last night addressed the slow jet and found idle.

I'm going to run what I have in up to the LSLC Roundup and see how it does performance and mileage wise. If I decide to tweek the main jets after that then it will be based on real performance numbers.

Drove her to work this morning, started with ease and was off choke withing a couple of minutes!

 

[77mustard40]

Final report, the carb performed flawlessly over the the last three days to Katemcy Rocks. Started with ease, idled without choke within a minute (mild temps helped), hot starts were ok and ran great on and off-road. I averaged 13.1 MPG for the trip to include what was burned on the trail.

 

[Pin_Head]

Tell you what: You get an A+ for perseverance. Most people would have thrown in the towel long ago, but you stuck with it and beat it.

 

[77mustard40]

Tell you what: You get an A+ for perseverance. Most people would have thrown in the towel long ago, but you stuck with it and beat it.

Never would have started down this path without your inspiration; and never would have finished without you and Jim. Learned a ton over the last few months, on to something else.

 

[Hugh Heifer]

Congrats. I have this thread bookmarked for future maintenance issues. Great info here.

Sent from my thing with Woody's junk.

 

[Sea Knight]

Final report, the carb performed flawlessly over the the last three days ... I averaged 13.1 MPG for the trip to include what was burned on the trail.

That's outstanding fuel economy. Probably more like 15 mpg if you factor out the wheeling.

Props on your patience and perseverance. It's good to know that we now have a carb expert in the hood.

 

[davegonz]

Kelly, your rig did really well this weekend on the trails. Hopefully, Craig will upload the pic of you going down that one section with your rear DS wheel 4' in the air.

So, how much are you charging to rebuild carbs? I'd love to have mine gone over.

 

[77mustard40]

So, how much are you charging to rebuild carbs? I'd love to have mine gone over.

I'm happy to help but I've been really busy rebuilding carbs lately, too bad it's been the same one over and over. I'm not sure I'm qualified to be in business but will help you out when you want to take it off. Fee can be premium craft beers for a successful rebuild, bad ones are free. Deal?

 

[davegonz]

Deal. I'd just like to get it cleaned out at the minimum.

 

[Rzeppa]

Jim C. carb totally solved my problem. I'll be sending the old one back to him as core after I get back from Moab. It'll be interesting to see what the post-mortem on it is. I can't say enough about what he does with our carbs on our old trucks. Put the rebuilt carb on (on a fully smogged 60, no small task, Mitchel manual says 2 hours, took me 2.5 hours for the compleate R&R), test drove and she drives like she just rolled out to of the factory.

Perfect!

 

[FJ40Jim]

Just got Rzeppa's carb on the test engine. The carb won't idle at all. The idle speed screw is turned up high enough that it is just starting to pull fuel outta the main nozzle. Back the idle screw down and it just dies. ICS is functioning. A quick peek inside doesn't show anything terribly wrong. A full autopsy will be done when the carb is being rebuilt for a customer.

 

[77mustard40]

Thanks Jim, hope you will post the autopsy results once they are in, just interested in the diagnosis for the sake of continuing education.

Sent from my iPhone using IH8MUD

 

[Rzeppa]

Just got Rzeppa's carb on the test engine. The carb won't idle at all. The idle speed screw is turned up high enough that it is just starting to pull fuel outta the main nozzle. Back the idle screw down and it just dies. ICS is functioning. A quick peek inside doesn't show anything terribly wrong. A full autopsy will be done when the carb is being rebuilt for a customer.

Indeed, there are a bunch of folks on the Rising Sun forum who are waiting with baited breath to learn the root cause. When the idle screw was not turned as far in as was the case when I pulled it and sent it to Jim, it would idle sometimes and other times not. As written previously there was an orientation sensitivity, when the rig was pointed downhill or when braking to a stop with clutch disengaged, she'd stall, but when pointed uphill or level she'd idle OK.

The rebuild carb worked flawlessly the instant I installed it, so that basically eliminated every other possible cause of the stalling issue.

 

[Dr Red]

Great thread -