Hesitation

[Pols497]

I recently purchased a 1982 712 M, when you first takeoff right off idle it hesitates. What could cause this . Any help would greatly be appreciated.

[Jim LaGuardia]

Well, if you just got it, you will have to start from square 1
Is it stock ignition/plugs/wires? Or is it civilian conversion/pertonix system.

Personally, I would start with timing/dwell(if equiped with points), then inspect/sync/adjust carbs and chech accellerator pump operation(see if the jets spray when actuated).
Now get to work

[audiocontr]

Mine started to do the same. I've noticed it increases as my fuel decreases... that is to say, when im low on fuel, the hesitation becomes substantially greater. I fill it up and we're back to normal

[Pols497]

It still has the stock ignition system. I checked and it sprays fuel when you hit the throttle. I purchased the civilian kit but haven't installed it yet. What does it time on as in degrees before top dead center, and how many quarts of oil does it take when you change the oil and filter.

[Jim LaGuardia]

7.5-8 qts 30 wt or 20 50 wt for the oil.
Timing instructions are in the civvy kit (3-7 deg btdc)

[edzz]

Mine started to do the same. I've noticed it increases as my fuel decreases... that is to say, when im low on fuel, the hesitation becomes substantially greater. I fill it up and we're back to normal

Try changing the fuel filter. Had similar situation plus auxiliary gas heater would not start. Changed filter, all good after change, dissected filter and was surprised by amount of junk that was not visible through filter housing. New filter shows much higher fuel level (in filter).

Ed

[Pols497]

Thank you very much. Whats going to be the best way to check and set the RPM's. I have never had any experiance with 24v systems.

[edzz]

I use a fluke automotive multimeter with an inductive pick-up for rpm. You will also need access to a carburetor balancing tool. For timing I use a 12 volt timing light hooked up to a separate 12 volt battery to provide power to the timing light.

Ed

[Jim LaGuardia]

Use a timing light with built in tach and connect to rear battery( battery that has ground the cable attached to it). This allows you to use 12v timing light and run engine
See, it's easy. For those with milspec shielded wires, just use a 6" piece of unshielded plug wire between the cap and #1 plug wire for the pick up signal

[Jimm391730]

When I first bought my truck (9 years ago!) i had a very noticable hesitation off idle; I thought it was carburation, but ultimately it was the stock ignition system. Replaced with the EI Civi kit and the hesitation was gone. Seems that a weak spark will work at idle, but as the throttle opens the cylinders fill up with more air and fuel and the weak spark isn't enough to get through it, hence the hesitation. A good strong spark will ignite any amount of air/fuel and everything will run well.

A separate issue last year with our other truck seemed to be the same problem - smooth idle and running, but blurbling and hesitation on acceleration. This truck had the civi kit already, so I went though checking coils, pertronix, wires, etc. End result was the 4500rpm module was failing, giving only 8V to the coil instead of the ~17V that it normally should have. Once the module was bypassed everything has run smooth.

Jim M.
712W and 710M

[joenagel]

When I first bought my truck (9 years ago!) i had a very noticable hesitation off idle; I thought it was carburation, but ultimately it was the stock ignition system. Replaced with the EI Civi kit and the hesitation was gone. Seems that a weak spark will work at idle, but as the throttle opens the cylinders fill up with more air and fuel and the weak spark isn't enough to get through it, hence the hesitation. A good strong spark will ignite any amount of air/fuel and everything will run well.

A separate issue last year with our other truck seemed to be the same problem - smooth idle and running, but blurbling and hesitation on acceleration. This truck had the civi kit already, so I went though checking coils, pertronix, wires, etc. End result was the 4500rpm module was failing, giving only 8V to the coil instead of the ~17V that it normally should have. Once the module was bypassed everything has run smooth.

Jim M.
712W and 710M

hello jim i have a 710 m that has the same problem. i have the hesitation and some time blurbling at the exhaust when idleing. how do you by pass the 4500 module thanks joe 724-282-3596

[Pinzgauer Pete]

Joe you have to do some research of the old posts relating to the 4500 rpm module there are dozens of threads that will describe where it is, what it looks like, and how to bypass it...

[Jimm391730]

The easy answer is that the RPM module has a six terminal connector -- two rows of three. Jumper the middle of the top row with the middle of the bottom row, you're done.

[joenagel]

Joe you have to do some research of the old posts relating to the 4500 rpm module there are dozens of threads that will describe where it is, what it looks like, and how to bypass it...

thank you joe

[joenagel]

The easy answer is that the RPM module has a six terminal connector -- two rows of three. Jumper the middle of the top row with the middle of the bottom row, you're done.

thanks i tried the jumper still hesitates i am going to check the accelerator diaphrams