FJ60 Intermittent Stall at Idle

[Rzeppa]

I don't have anything to add, but I am posting this diagram to the RS website just in case photobucket goes kaput someday in the future.

Cool! I saved a local copy as well.

 

[Rzeppa]

So that guy on MUD had an extra o-ring on his needle valve. So not sure if that's the same problem you have Jeff. Probably not.

Yeah, I saw that. I also got replies from both Jim Chenoweth and Charlie (Pin Head). I used to know Pin Head from 10-12 years ago when both of us used to hang out on the CCOT board. Jim says that the idle circuit gets fuel from behind the main jet, so that blows my theory that it comes from the top. I still need to set some time aside to pull the top off the carb again, and this time check the float adjustment. I have just never heard of a float going out of adjustment once it's set, it is so darn simple!

 

[Rzeppa]

Yeah, I saw that. I also got replies from both Jim Chenoweth and Charlie (Pin Head). I used to know Pin Head from 10-12 years ago when both of us used to hang out on the CCOT board. Jim says that the idle circuit gets fuel from behind the main jet, so that blows my theory that it comes from the top. I still need to set some time aside to pull the top off the carb again, and this time check the float adjustment. I have just never heard of a float going out of adjustment once it's set, it is so darn simple!

I took the carb apart again yesterday and checked the float adjustment. It was exactly 7mm if you include the gasket. Since the instructions said 7mm to the casting, I bumped it one mm, but when I put everything back together it didn't make a lick of difference. The fuel level is still well below the bottom of the sight glass. Not to mention I seem to have lost a rubber washer.

 

[Rzeppa]

Here's a good look inside the bowl. You can see the fuel level is way too low. You can also see how clean it is. The specks you see in the bowl are discolorations on the surface, they are not loose objects.

 

[Rzeppa]

Here's the rubber washer I lost one of, and where (I think) it goes. Notice the missing one over there on the other barrel. What does this do? What are those passages for?

 

[Rzeppa]

Here is my spare carb I have on my bench I use for practice and understanding stuff. Even though it came off a 60, it does not have those two passages, they are closed off.

 

[Rzeppa]

Update: Jim C. says on Mud that the rubber washers are for the HAC system, and since the HAC should always be on at our elevation, missing one won't make any difference.

 

[Rzeppa]

So if the float is adjusted properly, what else might cause the fuel level to be too low in the bowl?

 

[rover67]

Man, no idea...

If the float was full of fuel it's sit heavy...

maybe it is full of helium?


But seriously, maybe it is the wrong float? I am at a loss... Try forcing the fuel level up by adjusting the float way high and see what happens... surely you can force it up by adjusting the float way high right?

 

[RicardoJM]

I'm in agreement with Marco. At this point you can can consistently replicate the issue by pointing downhill. Adjust the float (don't worry about the FSM setting) to see if it can make the issue cease. If it does, there are likely other undesired effects from the float being out from spec - but you now have some insight into what conditions are needed and can dig further into why those conditions do not exist.

 

[PhatFJ]

Jeff, I went through this EXACT same thing on my 1975 and for the life of me, I could not find the answer. Mine would drain to the same location, the excelerator pump would still have fuel in it so I would pump it with choke on and it would start every time. I did not have the stalling issue, mine would not idle without running into the primary. So after about the fifth time pulling the thing out to see if I could find the problem, I decided to put everything back to where it was before I rebuilt it, while doing this I did a blow test through the idle jets just to check for restrictions and guess what, the main low speed jet that I was taking out (factory spec) was more restricted than the one I was putting back in (the old one) it had the restrictor at the bottom of the jet opened up or removed. I put the old / larger idle jet back in and the problem went away, I could adjust the idle back down to 650 - 700 rpm and it was fine. In conclusion, I could only determine that it was the ISKY cam that the PO had installed, reducing the idle manifold vacuum (which was around 11 inhg) there was no leak in the intake or exhaust... Why am I telling you all this? All I can say, it is not always the logical answer that solves the problem. My problem was in the idle circuit and had to have a low speed idle restrictor virtually removed but it worked.. Good luck!! By the way, the carb bowl still leaked down to where yours is when it sat for a few hours, never did find out where the fuel was going...

 

[Rzeppa]

Update: I am having Jim Chenoweth build me a carb. He's going to send it to me and I'm going to then send him my old one. He's certain he will be able to figure out what's going on with my old one. I still drive this rig just about every day.

Brian, I am pretty sure that this 2F has a long duration cam in it. It was a MAF motor and they are well-known for promoting their "RV" grind cams. It has a deep throaty growl I have never heard from a 2F with stock exhaust and have great midrange power. It also only makes around 11 inches of vacuum at 7k feet elevation.

 

[Rzeppa]

I got my Jim Chenoweth carb on Thursday and installed it this afternoon (leaving for Moab in the morning, talk about cutting it close!). All I can say is the man knows what he's doing. Runs perfectly, just like the factory intended, problem completely solved. I'll be sending the old one back to him for a post-mortem.

 

[PabloCruise]

I got my Jim Chenoweth carb on Thursday and installed it this afternoon (leaving for Moab in the morning, talk about cutting it close!). All I can say is the man knows what he's doing. Runs perfectly, just like the factory intended, problem completely solved. I'll be sending the old one back to him for a post-mortem.

Great that all is well!

I am really interested in Jim's assessment of what was going on with your carb.

 

[SteveH]

You must be relieved!

 

[Rzeppa]

Great that all is well!

I am really interested in Jim's assessment of what was going on with your carb.

I am too! I just got back from Moab yesterday, so I haven't sent the old one back to him. Do that sometime this week.

 

[Rzeppa]

You must be relieved!

I would be if I didn't have a blown head gasket...

Made it just past mile marker 3, you could see the rabbit valley exit sign off in the distance. The rig's at Hugh's shop in GJ, he's going to fix it for me and I'll go pick it up whenever it's done, hopefully by next weekend.

I got to drive Marco's 60 to lead Chicken Corner on Thursday, which I was supposed to lead anyway, then rode shotgun with Daniel on Fins on Friday and rode shotgun with Tim on Wipeout on Saturday. Twas fun, but would have nice to have had my own wheels...

Dave Kaiser gave me a ride home. Thank you everyone!

 

[SteveH]

Poor guy - hang in there! You now have stories to tell (more, anyway).

 

[PabloCruise]

I would be if I didn't have a blown head gasket...

Made it just past mile marker 3, you could see the rabbit valley exit sign off in the distance. The rig's at Hugh's shop in GJ, he's going to fix it for me and I'll go pick it up whenever it's done, hopefully by next weekend.

I got to drive Marco's 60 to lead Chicken Corner on Thursday, which I was supposed to lead anyway, then rode shotgun with Daniel on Fins on Friday and rode shotgun with Tim on Wipeout on Saturday. Twas fun, but would have nice to have had my own wheels...

Dave Kaiser gave me a ride home. Thank you everyone!

Serious bummer!

 

[subzali]

Wow, Jeff! What did you do to the Cruiser gods so that they put these dampers on your Cruise Moab vacations? Did it let go suddenly, did you peg the "H"?