'77 20r starting problems...arrrg
 

Hey everyone i am hoping for some advice on where to go next. I have 1977 chinook pop up camper with a 20r in it...all seems to be original. Then thing ran great until parked one day a few years back. And it's still doing the same thing today as to the reason i parked it. It's getting spark..i just replaced the fuel pump yesterday, assuming that was the problem, and it's getting fuel to the carb...when i crank it and and give it gas it 'runs' and revs up but as soon as i stop cranking the starer it dies and won't run. I would really appreciate any advice on where to look next, i'm really stumped and i really want to take my son and his friend camping this weekend. thanks in advance for any responces.

This weekend?..good luck! :)

It's getting spark at the plugs?

So it fires, but then dies? First, I would put new fuel in it. Obviously if it was doing this before, there's more going on than the fuel, but old fuel won't help the problem at this point.

Does the carb have a sight glass? Can you tell if it's getting too much fuel (ie flooding)? So it dies as soon as you stop turning the key? It won't stay running if you keep your foot on the gas?

I'm leaning towards a carb problem, but it's hard to say.

Also make sure there are no vacuum lines disconnected...

haha yes this weekend *crosses fingers...thanks for the reply Zach, i've checked all the vacuum lines, but i'm going to re-check them all...and i can see fuel in the site glass on the carb..i took out all of the plugs this a.m. and cleaned them, they had some black sooty stuff of them but it easily wiped off..and yes, it acts like it's going to take off and run but when i disengaged the starter and move the ignition to the 'run' position it immediately dies...it may be a flooding issue...and i just installed the gas tank yesterday...i cleaned it out a few days previous and let it air dry and i put new fuel in it. I tried to start it this morning without depressing the accelerrator...and it wouldn't fire at all...but when i gave it gas while cranking the starter...it started to fire up...i feathered the accelerator as i stopped cranking the starter...and it died almost immediately...i guess it may be the carburetor, i was hoping i was over looking something simple.

and oh yah...it is getting spark at the plugs..i took a plug out last night and put it back on the wire and set it on the air cleaner and turned the ignition over and it had a really strong spark...

There are definitely rebuild kits. If you can find a tag on the side of the carb it should have the model number on it, and that will get you a rebuild kit. They aren't pricey, but there's a lot of little parts (in the carb. just gaskets I think in the kit) so you need to be very methodical about the rebuild.

So, there's fuel in the sight glass, but nothing going into the "throat"? You could try spraying the heck out of it with carb cleaner first...that would at least be a "band aid" until the rebuild.

Also not a bad idea to spray in some starter fluid and see if it will start for a second with that. Then you know it's just not getting fuel.

Yah i couldn't see anything spraying into the throat at all...and it didn't smell very gassy...and yah there is fuel in the site glass, about half way full...and i blew into the fuel line leading to the carb and heard air passing into the throat of the carb and then i filled the line with fuel and blew into it and i couldn't really blow all of the fuel into he carb...i'm going to take your advice and clean it out really well with carb cleaner...and then go from there... i'm about 12 miles to the nearest internet connection so i might not be back for awhile..i'm kind of in the boonies...thanks for your advice and your help!

Good luck.

You can always look for a used carb in better working condition to swap onto your truck while you take your time rebuilding this one. But I doubt there are many more trucks like yours in wyoming than there are up here. I'm not sure of what other year carbs will swap onto your truck without modifications...maybe somebody else around here does?

I’m having a similar problem with my 77 camper. Help!
 

It runs as long as I am turning the key. Less than a year ago we replaced the fuel pump. A few years ago we put a weber carburetor on. This started in mid January during that real cold snap we had. I put a couple extra gallons of gas in the tank and Replaced the fuel filter, checked my fuses as well as replaced ignition switch. Any advice?

Have you tried to "hot" wire the ignition? If it fires ONLY while in the start position, suspect ignition switch wiring. Run a 12v jumper wire to your ignition.

When you say "It runs as long as I am turning the key" what do you mean? What is running? The fuel pump or the engine or both? And by "turning the key" does that mean the START (cranking) position on the ignition switch? And it doesn't "run" in the "on" or RUN position?

If you only meant the fuel pump runs and I am correct in my guessing about the key positions, I'd suspect that your fuel pump relay has bad contacts on it's RUN side. New, original style relays for the '75's to 78's are no longer available from Toyota. However I do have a fix for this for a replacement relay. Here's the link to my write-up: https://www.yotatech.com/forums/f114...m-info-309287/

It's also possible that you have a bad Oil Pressure Sender switch. That switch also operates the Fuel Pump Relay & determines whether the Fuel Pump gets voltage from either the START side or the RUN side of the Ignition Switch.