By Steve Carrett (Stevo) on Unrecorded Date: Edit

As well as the general tips I am wanting to get, I am having some big hassles at the moment with the 500 Superchief. It is the "Lil Truck" option and has the 484cc Chaparal engine. Here is what is happening;

Ok, each day I would go to the garage, start the Attex, let it idle for say 1-2 minutes, drive out the gate, down the street, down a 4wd access track, out on to the beach and then drive it up and down the beach at low tide on the hard sand. After about 1/2 to 3/4 of an hour, the engine started to miss, I would then take it home and park it in the garage. Next day, I would do the same and about after 1/2 to 3/4 of an hour a miss occurred. We keep a spare set of plugs in the back of the Attex (for emergencies) and I swapped the plugs over. The plugs I put in had a lower number on them. The last time I took the Attex out (today) it got a WHOLE lot worse. After about 1/2 to 3/4 of an hour the miss occurred again, but this time as I was crossing through the soft sand to get on to the 4wd track, the engine was wanting to die. I had to put the levers in the vertical position a number of times to build up the revs to keep going. I was really worried the Attex was not going to get me home.

When I talk about the miss, the engine makes popping, slight banging and rattle noises. Runs rough...

I appreciate any help you can give me.

Thanks,
Steve

By david berger (Davidrrrd) on Unrecorded Date: Edit

steve she's maybe geting hot on you, try a lil more oil in your mix,
also make shure your gas filters are clean,
and gas tank vent works,(in case it's starving somehowif you notice theres a point in the throtle opening that at speed more dosent add aditianal power and till some point when you release the throttle it dosent chainge anything, the point at wich the last amount of chainge acores at is max opening,
if you open more it will lean out and overheat it,
this can ocure from several things, wich can include stupid stuff like dirty filters, poor vent,ect..ect..
you just never keep throtle open all the way when half way is all that chainges anything becaus it leans out unessesarely wich overheats it.

By roadwolf on Unrecorded Date: Edit

steve, do you have a mukuni slide or a tillotson carb, and what ratio of gas oil are you running?

By Steve Carrett (Stevo) on Unrecorded Date: Edit

Hi Guys,
Thanks for the responses...
I am not sure what type of carburettor it is off the top of my head. I am pretty sure it is the standard carb Attex fitted to the 484cc Chaparal. If that helps???
I am running un-leaded gas with a 20:1 oil mix. The oil we use isn't synthetic, but 2-stroke type oil (not marine).
I never even thought of checking the filters, vent etc, etc. Should I consider insulated gas lines??

By r.wolf on Unrecorded Date: Edit

steve,
sounds like you are running rich to me. but you say 20:1, now i am not sure. are you sure it's exactly 20:1? what brand a plug ? ngk lower #'s are hotter. what kind of carb has he got? you other attex guys.

By jim1964 on Unrecorded Date: Edit

I had the same issue with my G50B, 484CC Chapparal on the max 4, turned out the problem was not related at all to the mix or carb-the issue is that your engine runs fine cold, once it heats up the rings get loose, the suctioon for the fuel pump off the engine goes dead, inseat of giving you suction you get blowback and the engine starves because it cannot get fuel. We broke my engine apart and the pistons were sratched badly, gouges out of the cyliner wall on one .

Now I am lost I was going to tray and rebuild it before I noticed the walls were very bad-anyone know where you can get spare cyliners, Pistone and rings?

By r.wolf on Unrecorded Date: Edit

1964, the fact he has to pull in the laterals and fan the throttle seems there is aboundant fuel, if starvation would be the case, it would just die.