2004 Carryall 272 fe400 will not rev off idle.

[jwaddell]

I just typed up a whole lengthy post, when I went to post it, my account had been deleted... I'm off to a great start.

2004 Carryall (bone stock, FE400D) came to me to have a new exhaust installed. Installed new exhaust, noticed spark plug cap was loose. Cinched it back on and whammo. Won't rev off idle. Before we get going, I have an extensive history in ATV'S, PWC'S, I/O's inboards, outboards, BBC, SBC and all auto's both foreign and domestic, and creeping this forum for info pertaining to my exact problem (can't find a thread.)

Sequence of events:

1- Replaced old exhaust with new. Bang, wont rev off idle.
*then replaced new exhaust with old*
2- spark air fuel. Replaced fuel filters, siphoned tank bone dry, cleaned carb (knit pickey clean,,,, 5 times now) Replaced plug (NGK BPR5ES gap set at .030 - no change .028 - .035) Checked air filter (like new, no debris noted) Still runs like poo.

Definition of runs like poo. Idles great, 1080 RPM would idle all day long if you let it. Give it any amount of throttle and it just flat cuts out, cuts out to the point I suspected intermittent spark failure of some sort. Tested all aspects of ignition system to the point of buying a digital read out multi meter, and matco spark light (best way I can describe it) off the spensive truck. Everything spec'd out except the plug cap, which I replaced, no change. If I feather choke or place my hand over the intake it does run better. Also if you loosen the external jet on the carb 1/2 - 3/4 turn it also helps (gets through the midrange, but starves on high end)

3- read an article on here about valves not closing, have not popped the head but I did remove the valve cover and verified valves are traveling specified distance. (-- NOT FOOL PROOF I KNOW--)

4- Disconnected RPM limiter no change

5- disassembled and cleaned fuel pump and breather no change

6- talked to club car they insisted that carb had to still have debris in main jet. Tore it down again, soaked it in carb cleaner overnight, still no change.

I am at a loss and worse, I am beginning to second guess my work. Does anyone here have any intellectual input?

[lockman1]

If it idles at 1080 rpms all day long... I'm guessing this is a "Key Start" cart?
(if so, you'll need to mention that every time you have a question, 90% of us have "pedal start" carts!)

*EDIT* I just reread the whole post...

The FE engines don't run/run like Poo without the complete intake system hooked up and sealed!
Check for air leaks in the system, air box lid closed. and latched tightly,
cracks in the intake tube, bad carb gaskets.
While it's idling, spray carb cleaner all over the system and see if there's a change in rpms, if so, you found a leak!

[raydhd]

Have you run a compression test?

[jwaddell]

I will do a compression test today.

I was 90% sure intake was intact and sealed I will get the other 10% today.

[jwaddell]

Lockman, Sorry it took so long to respond. A corner of the air filter was displaced (pushed down) on the hinge side in the airbox. Straightened the filter out locked the top back down and it runs like brand new!! I can't believe how finicky these machines are.

[lockman1]

Glad it was that easy!