I took the samurai for a test run and when it gets to 3000rpm it bogs and sputters real bad. But if i put the clutch in it will rev fine. It losses all power at 3000RPM. I put a brand new exhaust and ignition system on. It is only under load when it bogs down. What could cause this ?.

Tell us more!

Carb or EFI?

What ignition?

Vacuum leak, or timing maybe 

Tell us more!

Carb or EFI?

What ignition?

It is a stock carb with a MSD blaster coil with new plugs,wires,rotor,and cap.

Setup is just like mine, except the carb. Check the distributor's vacuum advance membrane. Remove disty's cap, unplug vacuum line(hose) from carb side and suck. If you feel that you're sucking air through the hose or disty's rotor isn't turning then you did find the problem.

Did you placed 0.8 ohm ballast resistor before the MSD coil?

Setup is just like mine, except the carb. Check the distributor's vacuum advance membrane. Remove disty's cap, unplug vacuum line(hose) from carb side and suck. If you feel that you're sucking air through the hose or disty's rotor isn't turning then you did find the problem.

Did you placed 0.8 ohm ballast resistor before the MSD coil?

I did place a .8 ohm ballast before the MSD. I checked the vacuum line on the distributor and i tried suction on the vacuum line i didn't get any suction but the rotor did not turn. I could hear the vacuum advance move when i applied suction.

How old are your wires, cap and rotor? I am not as smart as some of these guys on the forum but more spark from the new coil makes for easy carbon tracking inside the cap (spark scatter?) Don't know the correct term but it happened to me on another toy and I went and replaced all three and everything was fine but I never knew which single thing it was. Not to say that is your problem but just food for thought. Also how are your engine grounds? I normally put a dedicated ground strap from the starter motor (one of the mounting bolts) to the frame just to be sure. Hope this helps some. Good luck and keep us posted on your solution.

Woops! Just went back and read through all your posts........Forget all of my info and just check for good grounds......

I was wondering if the choke could cause the engine to sputter. But why would it only happen when the motor is under load.

I was wondering if the choke could cause the engine to sputter. But why would it only happen when the motor is under load.

Could be a choke issue, have you tried putting the stock coil back on? If I am reading this post correctly, the problem started after the coil and exhaust were replaced?

Quote from: Dimitros on March 23, 2009, 03:06:00 PM

Setup is just like mine, except the carb. Check the distributor's vacuum advance membrane. Remove disty's cap, unplug vacuum line(hose) from carb side and suck. If you feel that you're sucking air through the hose or disty's rotor isn't turning then you did find the problem.

Did you placed 0.8 ohm ballast resistor before the MSD coil?

I did place a .8 ohm ballast before the MSD. I checked the vacuum line on the distributor and i tried suction on the vacuum line i didn't get any suction but the rotor did not turn. I could hear the vacuum advance move when i applied suction.

Well, how could you hear the vacuum advance moves and seeing nothing moves? There's a magnetic pickup part inside your disty, it's covered with black plastic cover with "do not remove" sing, it should move relativly to rotor. That black thing is moving for aproximatly 1cm around the rotor when suction applied, then when you release your "vacuum" it should slightly go back to it's original position. Here are some pics:

I checked the vacuum again and did notice the black cover moving slightly. I think it might be the choke causing the problems.

I took the samurai for a test run and when it gets to 3000rpm it bogs and sputters real bad. But if i put the clutch in it will rev fine. It losses all power at 3000RPM. I put a brand new exhaust and ignition system on. It is only under load when it bogs down. What could cause this ?.

Clogged fuel filter. Bad fuel...

-Eric

a $10 HF timing light you can check
static timing
mech adv. timing,
vac adv. timing.

ALLabove  ok?
then back to carb.

your jets are dirty.
car is going lean.

all carbs, need to provide more fuel under more load.
(same with EFI )  { map or maf, as approp)

on a carb how this happens varies all over the map.

it takes little fuel to rev any engine with no load (you saw that)
and if going up hill , max.

usually it is 1st to 2nd gear power shifts up a hill , is worst case on all cars

I can prove that with my MAF data logger.

Carbs need to be boiled out (chem cleaned) and kitted every 100k.

I have no carb pages.  (they are mostly dead here since 88)

http://carfix.stufftoread.com/

Mudslinger, Where are you at on solving your problem? Have you solved it? Hope so because it looks like you really are going to have a great ride when you get it DIALED IN !