Help with loss of power in my Dump Truck

[EddieWalker]

I have a 1983 F-600 Ford Dump Truck with a 370 gas engine. When I bought it, I did a compression test and had from 120 to 140 pounds of preasure. It fired right up and ran good.

After using it on a few projects, I parked it for six months. When I tried to start it, it wouldn't start. During this time of trying to get it started, I replaced my roter, wires, plubs and rebuilt the carberator. That got it going.

Yesterday it started out good moving dirt, but it quickly started loosing power. It's at the point now that it doesn't have enough power to make it over a small dirt mound. Today I started it up and tried to drive it empy on flat ground and it was just about impossible. No power and I had to really ride the clutch to get it to move. Then it kept backfireing, which is something new.

I'm hoping some of you with more knowledge of gas engines can through out some ideas and suggestions.

It could be the carb and I've thought of replacing it with an aftermarket one without the govenor. I also thought about a new distributor that doesn't need the computer module. Just strip the engine down to the basics.

It's not street legal, no smog or anything else is needed, just some more power.

Thank you,
Eddie

 

[nobull1]

I assume from your post it was a progressive thing and not instant? If it was progesssive how about something as simple as a plugged fuel filter. After sitting six months who knows.

 

[rswyan]

How many miles are on it ?

........ timing chain and/or gears ?

 

[rdln]

If It is the timing gears and chain try advancing or retarding timing slightly,
I would think a small bore big block thats meant for trucks would have the most durable noisiest chain there is but you never know.

 

[EddieWalker]

The air filter is brand new. The power issue became apperant after getting it running after sitting. It went from bad to really bad, to just about impossible in just a day.

The timing chain is something I was discussing with Golfgar, who's visiting me right now. Broken teeth or a stretched chain make sense to me because of the loss of power that is getting worse and the backfiring that started today.

I've checked my manuals, but can't seem to find what the timeing is supposed to be. Any ideas? Maybe a good website with engine specs for a 1983 Ford 370 or 6.1 V8.

Thank you,
Eddie

 

[RodgerF]

Eddie,

Try here.

I had similar problems on an '87 F250 with the 460 engine. I traced most of my problems back to soft/cracked vacuum hose. Also had the distributor vacuum advance diaphram go bad causing a vacuum leak and of course no ignition advance.

Good luck

Rodger

 

[MikeD74T]

Likely that your timing chain has jumped one tooth. If so,you can rotate the distributor forward a little & get some of the power back. That still leaves the valve opening/closing late so the timing chain/gears should be changed soon. Have used this to limp home a couple of times. If it jumps a couple more teeth it can cause piston & valve interference which is a very bad thing, bent or broken valves, pushrods etc.

 

[Bird]

</font><font color="blue" class="small">( Likely that your timing chain has jumped one tooth )</font>

Sounds like a very good possibility. I've only had that happen once in my life. When I was driving a school bus ('52 International), I stopped to let kids off one place and when I started up, it backfired and died. Then it started easily, would sit and idle, but simply would not move itself at all even in the lowest gear on level ground. No matter how much I revved the engine or how slowly I eased out on the clutch, it would just kill the engine.

 

[JerryG]

Eddie,
Those years used an aluminum EGR plate under the carb. The plate would detonate and allow a huge vacuum leak. The plate with the valve on the back behind the carb can be removed and replaced with a heat dissipating gasket set. Look at that and see if that is causing the problem.

 

[TOMLESCOEQUIP]

Eddie.......I had the same problem with my 2003 arctic cat 400 that sat for several months without use. Spitting, backfiring, hard to start etc...........It turned out to be the gas. I had the tank clear full, but stored the quad in an uninsulated barn, where it got a lot of hot & cold cycles. The aeromatics in the gas boiled off, leaving stuff that looked & smelled like gas, but wouldn't vaporize to form a flammable mixture any more. I a short word, today's gasoline is pure crap & has a shelf life of about 6 weeks. Try draining the tank & carb & starting with fresh fuel & see if that doesn't fix it for you.