'78 fj40 bucking

[Devilmans Hand]

Yea, this is another thread started by me.

I'm addressing the stuff i broke this Mem day.
Tail light lenses are only $17 from the dealer, and mine now contains a beercan light section divider because the original is somewhere on Trickle Creek.

I started ripping off my rear plastic fender flares on the trail, do i need them in VA and surrounding states to be legal with regular plates? I'll measure how much the wheel extends outside the body sometime in the near future if it matters.

I'm pretty sure that I need some more backspacing on my wheels. Jon pointed out that my wheels do not turn as far as everyone else's wheels. I can also see a nice shiny line where something has been rubbing on the inside of the wheel when the wheels are turned as far as they'll go.

now comes the important part

When I was coming back from the trip going up that huge hill on rt. 17/50 the cruiser started bucking in 4th gear. I figure all the off camber and jarring on the trail worked some **** loose from my fuel tank elsewhere into the fuel line. I changed the fuel filter, stock type right before the fuel pump, but I'm still getting some bucking when under load, usually around 1800rpm.
This thread, https://forum.ih8mud.com/40-55-series-tech/310245-gas-starved-4th-gear-only.html
also mentions that this could be ignition related. Everything under the hood seems tight and where its supposed to be. I have a stock '78 FJ40 CA Carb Smogged and stock type fuel pump. I don't have a timing light or any special tools. Does anyone have any ideas of what could cause these symptoms to suddenly appear after wheelin a bit?

 

[Devilmans Hand]

forgot to mention that I also bent up my exhaust a bit, but didn't crush it shut or rip any new holes.

 

[76FJ40]

Old Cruisers frequently have more than 1 fuel filter so look a little further. Was it pinging under a load?

 

[Devilmans Hand]

No pinging that I can tell. I'll go double check that there isn't another filter hiding.

 

[greytandy]

Old Cruisers frequently have more than 1 fuel filter so look a little further. Was it pinging under a load?

Sometimes upstream and downstream of the fuel pump.

 

[Devilmans Hand]

Yup, Only have just the one just before the fuel pump unless there is one coming right off the tank under the seat somewhere. When I replaced the old filter and drove it around I did notice that it now has some more pep to it. In the morn i'll warm up the engine, take off the air cleaner and slam my hand on top the carb to see if i can clear any blocked up spots in the carb.

 

[Jakes40]

It was mad at you for not taking it out for the second day. Once the old cruisers get a taste for to off road they want more and more. All you can do is feed the hunger for the rocks, positive reinforcement CMCC is just around the corner.
Hope this helps

chris


P.S. Is there a screen on the card inlet? Might have something cloging it or the pickup in the tank after sloshing around on the rocks.

 

[kulangot]

Sam,

Call me and I'll walk you through some diagnostics.

A few things to do first.

Start it up at night and look at the engine running. See if you can see any arcing at the plug wires. Take a spray bottle full of just water set on mist and hose down the plug wires and see if you get a miss. Check the coil wire as well. Before you do this, look for a worn spot on a wire and move the wires around a bit before you get them wet. This might help find a place where it's arcing.

Grab the distributor and see if you can twist it. It may be loose and you may slipped your timing. Get a timing light and check it.

Pull off the cap and look for cracks in the cap, arcing or signs of water getting in there. Look for signs of the button on the top of the rotor being worn out.

This would be a great reason to get a dash mounted vacuum gauge. Once you learn how to read one, you could glance down at the gauge and it would tell you more about the problem based on how the needle reacts to the problem. You can also hook up a small 12V light to the ignitions system as a "tattle tale". If the light blinks in a manner that corresponds to the bucking, then you have a power problem.

You can also try and just get down to an empty tank and then dump the rest. Have the tank cleaned and replace the fuel lines - all of them. Mark Algazy once showed me a section of fuel line that had rusted from the inside out and filled the carb with rust flakes. The line looked great from the outside - it's 30 years old, replace it!

 

[Devilmans Hand]

ok, I have an update.

I checked all my wires and connections and was good there, but couldn't get the distributor cap off to check the internals.

Slammed my hand on top of carb a few times in hope of clearing any blocked passageways.
Took the cruiser for a run to sears hardware, about 10mi each way, to get a timing light and vacuum gauge, still had bucking in 4th gear around 1800rpm on the way there.
On the way back i had to take a sharp left hand turn up a hill from a dead stop and in 2nd gear around 2500rpm and it suddenly stalled out. Start it back up and no more bucking. I started from a dead stop on level ground in 4th gear and no bucking.
I'm thinking that whatever crap was in the line cleared itself?

I also forgot to mention that the secondary in the carb drips fuel rather than perfectly spraying it. I'm thinking this contributes to the problem?

and Colangut, I lost your number. Could you send it to me again?

 

[Felix]

My guess is timing.

I say that because that was my problem. For the last year or so, I've had the same problem. I'd set the timing with a light, still have the problem, and start chasing down fuel filters, ignition, etc. I finally decided to just play with the timing without the light, and that fixed it.

Not that a timing light isn't a good idea, but in the mean time before you get one, do this.... Let the truck warm up and idle. Loosen the bolt at the bottom of the distributer and turn it a little one way or the other until it sounds like the engine is idling better (or faster, maybe). Then take it for a drive on the highway and see if it's better. If so, adjust your idle speed back down.

Worked for me. Runs like a champ now.

 

[Thornton]

ok, I have an update.



Slammed my hand on top of carb a few times in hope of clearing any blocked passageways.

Big hammer works better Do you think maybe the floats may be sticking?

 

[Devilmans Hand]

don't think so. In one of the links i read about the bucking problem someone said to take the aircleaner off when the engine was running and slap your hand on top of the carb to create a vacuum spike then rev the engine so it doesn't stall out.
At the last tech day at convenience Ed said that the fuel dribbling out is likely the result of a little tab or piece of metal that needs to be properly bent or something of the sort.
I'm planning on a Trollhole non-usa type carb in the future, mid july, so i haven't given this problem too much mind.

 

[kulangot]

Does Troll Hole sell new non USA carbs?

I'd recommend a Mark's Off Road rebuild.

 

[Devilmans Hand]

yup, brand new reproduction non-usa Carb. Cheaper than marks rebuild I believe, and very limited down time. I'm desmoging soon too and want go keep all the smog gear intact in case I need to put it back on.

 

[76FJ40]

yup, brand new reproduction non-usa Carb. Cheaper than marks rebuild I believe, and very limited down time. I'm desmoging soon too and want go keep all the smog gear intact in case I need to put it back on.

My son Ryan has a Trollhole carb and is very pleased but they may not have all the vacuum ports necessary for complete functioning of the smog gear. Mark rebuilt the carb on my 45. I'm very pleased with the performance but the down time was considerable.

 

[Devilmans Hand]

Yea, since its a non-usa type it wont work with the smog gear. I just don't want to have to modify my original CA set up Carb just in case I have to resmog the cruiser for whatever reason. Then I can send out the CA set up Carb to be rebuilt as a spare at my leisure.
I regularly drive my cruiser, so downtime is unacceptable. plus that is how bigger projects start. "Well, I already did this, so I might as well..." then ill have the whole thing taken apart in my parking space.

 

[kulangot]

Yea, since its a non-usa type it wont work with the smog gear. I just don't want to have to modify my original CA set up Carb just in case I have to resmog the cruiser for whatever reason. Then I can send out the CA set up Carb to be rebuilt as a spare at my leisure.
I regularly drive my cruiser, so downtime is unacceptable. plus that is how bigger projects start. "Well, I already did this, so I might as well..." then ill have the whole thing taken apart in my parking space.

That is cool. I wonder where he found them?

I would go that route myself. I've bought a few of those new from SOR.com but i don't think they have them anymore.

 

[Devilmans Hand]

That is cool. I wonder where he found them?

I would go that route myself. I've bought a few of those new from SOR.com but i don't think they have them anymore.

He's getting them from somewhere in southeast asia, I'd guess Indonesia or somewhere about those parts.

 

[kulangot]

Cool.

Vienna local Jim (White HJ45) is moving to SE Asian for three years. He's bringing the 45 along to get it's 2nd restoration so he'll be in with the locals.

Maybe he can source some parts for us.

Glad to hear the new non usa carbs are available again. A new carb, distributor and super tuneup have been the best mods I've ever done to a cruiser - inc. v8 swaps...

 

[Devilmans Hand]

slightly OT, but what distributor would be the upgrade from the 1978 small cap electronic in my 40?