40 bucks on inclines....help!

[CruiserStuff]

Just drove the 40 on the freeway at about 60-65 for about 2 hours with no problems at all....very smooth. But once I hit an incline, the truck started to buck and lose power.

If I jam the gas all the way down, it gets better for a second and then starts bucking even worse. When I pull off the road, it idles fine and I get back on the road, it does okay again until I floor the gas or hit any substantial incline.

Any help? FYI, this is a bone stock 2F with a just-rebuilt carb by Mark's Offroad - nothing is modified....

 

[John Smith]

Just drove the 40 on the freeway at about 60-65 for about 2 hours with no problems at all....very smooth. But once I hit an incline, the truck started to buck and lose power.

If I jam the gas all the way down, it gets better for a second and then starts bucking even worse. When I pull off the road, it idles fine and I get back on the road, it does okay again until I floor the gas or hit any substantial incline.

Any help? FYI, this is a bone stock 2F with a just-rebuilt carb by Mark's Offroad - nothing is modified....

How many fuel filters are you running and are there any rust bits in them? It sounds like when you hit an incline something is moving and clogging the fuel system that is not an issue when flat.

 

[CruiserStuff]

Good call....that's what I was thinking too. I'm just running the stock filter so that will be the first check. Thanks John....

 

[fireflyr]

Would an improper float level do that? What kind of carb are you running?

 

[Vicm]

Good call....that's what I was thinking too. I'm just running the stock filter so that will be the first check. Thanks John....

Like John said,
If you have restricted or reduced flow of fuel , it might do that on an incline and drive normal on a flat.I have been there before.
If this engine is new to you, just replace the filter.
Is this a stock fuel pump?

 

[bsmith123]

float

Ive never really looked at the FJ40 carb yet but I have read that a float not shutting off can cause probs like that. if the float does not shut then fuel spillage from it is killing the engine

Also you should be able to see if it is getting to much or too little fuel by reading the spark plugs

Spark Plugs

 

[flippin sweet cruiser]

Not sure what kind of distributor your running but mine did the same thing when my points went bad.

 

[calixto]

Just had the same problem a couple months back when I switched over to a new carb. I kept getting small bits of debris into the carb. Exact same symptoms you are describing.

 

[nspctr1]

maybe debris / rust in the tank also.

 

[CruiserStuff]

I'm running a stock fuel pump and a stock carb (just rebuilt by Mark A.). I have a new fuel filter coming on the truck today - will be here at noon. Hopefully that will take care of it (try the cheapest fix first!).

Calixto - If it is debris in the carb, what's the easiest way to clear it out?

The dizzy is out of a 3/79 truck - electronic.

It might be the float, but I'm not thinking this is the case here....could be wrong.

 

[calixto]

The shop that installed my carb went back through and cleaned it out again. Happened twice because of the improper way it was installed by them. The debris in mine was in the top end of the carb so it wasn't a huge deal. I ran two clear fuel filters one between the tank and the pump and one between the pump and the carb to keep an eye on stuff coming into the carb.

Eventually once I understood how f'ing stupid the mechanics at the shop I was using were I had a cruiser buddy fix all the misstakes they made. They had the fuel inlet plugged and gas feeding into the return location with some crazy JB welded Banjo fitting. The small flakes of JB weld material was getting into the carb.....unusual situation but a lot of comments were that debris can often gets into the carb when switching them out just for the simple fact of bending and messing with the lines when you are working on them if they are older. I will post a link to the thread I started about this below.

 

[calixto]

https://forum.ih8mud.com/40-55-series-tech/253760-rebuilt-carb-problems-higher-speeds.html

 

[CruiserStuff]

Calixto - I remember reading that thread and the headaches you endured. I know that Mark A. knows what he's doing with the carbs, but maybe something got jostled loose and found it's way to the carb. I'll start with the filter and, fingers crossed, that will take care of it.....

 

[calixto]

Yeah, my carb was re-built perfectly too...it just boiled down to the shop that installed....they fxxxed it up with the weird wrong Banjo fitting/incorrect routing. BTW, they also stripped out the threads on the return port they were using so we ended up having to replace the whole air horn section (thanks Degnol) and my buddy(crusierbrett) ran a custom hard line properly. Learned my lesson with that whole escapade.

 

[CruiserStuff]

The carb was installed on a 3/79 engine that TLC in Van Nuys installed for me and they are pretty meticulous. I talked to Jay and he said that it sounds like a fuel filter, too, so I'm really hoping that is the case. I really don't want to break down the carb to clean it out....it's raining outside and the snow is coming (they say). I've gotta plow the storm so I'm hoping it's a simple fix.....

 

[fjwagon]

I was going to say when it start bucking trying shutting off the engine and check your sight glass on your carb.

 

[CruiserStuff]

fjwagon - good tip....I'll try that if the new fuel filter doesn't solve the problem....

 

[fj404life]

You could try the old farmers trick...

Get the motor running with the aircleaner removed from carb and the threaded stud unscrewed that the aircleaner fits over. Now you can slap your hand against the top flat intake of the carb.

What your going to do is rev up the motor real high...then slap the palm of your hand on top of the carb. This will create a huge vacum and suck any bits of crap out of your jets etc. The motor will want to stall when you do this. Dont let it. Take you hand off and blip the throttle a couple times before it stalls to help clear out all the extra fuel you just sucked up into the motor. If it stalls on you ya may need to switch plugs as they will be fuel soaked. Try this a few times...see if it makes a difference. It really works sometimes!



I would put a new filter on first.

 

[cruiserbrett]

Sounds like the power valve is not connected... based on the description that it pulls for a second, the accelerator pump is working but the secondary venturi is not passing fuel, or the power valve is not functioning. some later carbs power valves are controlled by the VSV... post pics of the carb...

Dont forget to check the motor mounts?

 

[CruiserStuff]

Yeah, I think I located the problem....

What do you think?!

I put a cheap in-line filter in its place.....

and will run it until I see if more **** works its way out. Then I'll put a new stock filter in (I do like stock equipment).

Anyway, she runs like a top now, so I'm gonna strap on the plow blade and get ready for the snow....they're predicting a foot to two feet over the next couple days.

Thanks to everyone for the help. As always, you guys rock....