620 Engine quit- quick question

[rover215]

Was driving my '77 620 for 3 months- no problem. In fact, it was running great the whole time (I've only owned it for around 3 months). Drove it to a bike shop to do some quick business, killed it for maybe 20 min, then started it and took off. About a block and a half later, it sputters and dies. I could get it started with full choke but I had to floor it to keep it BARELY running.

Turned over great but wouldn't fire. Tried some starter fluid but it wouldn't even start with that- not even for a second. There's fuel in the sight glass of the carb so I'm guessing it's getting fuel. The plugs, cap and rotor don't look awesome but it was running great before this happened so I don't know why it would just die like that.

Probably premature to ask what's going on with it since I haven't replaced any of the aforementioned bits. I'll do that tomorrow. Oh- it's got electronic ignition. I'm not a mechanic- just a mildly informed tinkerer. Any thoughts?

[Cuts metal like mad]

check for spark.

[rover215]

so I might be getting enough spark to get it barely running but not running smoothly? Maybe a couple plugs are bad? I'll check it and post a reply later.

[rover215]

Got a new set of plugs, wires, dizzy cap and rotor and no change. Turns over but will not start. Plenty of spark from the '79 or '80 dizzy. WTF?!

[Cuts metal like mad]

well try dumping a tiny bit of gas down the carb, if it doesn't start then its time for a compression test. You say you got spark, so with GAS not starting fluid, it doesn't start then compression is the next thing. If compression comes back F'd or even if not, check your valve lash.

[mike]

Check to make sure your manifold bolts are tight and your carb is bolted down tight to the manifold... Snug is plenty tight enough, I always use a short stubby 1/4 inch ratchet just to make sure I dont get overly torque happy when tightening stuff down, theyre easy to strip.

 

Assuming its a hitachi... are all your wires and vacuum lines hooked up on your carb?

[1972.5 dat]

Ck the dist cam shaft that run the dist and oil pump the gear teeth my be strip on crank shaft my did the same going down the road my .02 help

[Cuts metal like mad]

Check to make sure your manifold bolts are tight and your carb is bolted down tight to the manifold... Snug is plenty tight enough, I always use a short stubby 1/4 inch ratchet just to make sure I dont get overly torque happy when tightening stuff down, theyre easy to strip.

 

Assuming its a hitachi... are all your wires and vacuum lines hooked up on your carb?

 

This would make sense if the truck started running bad and then not running... it would be strange to suddenly stop running altogether from a vacuum leak, but I suppose its possible. Good call either way.

 

Ck the dist cam shaft that run the dist and oil pump the gear teeth my be strip on crank shaft my did the same going down the road my .02 help

 

This is nearly impossible since he says he has spark... but I've been wrong before and I'll be wrong again.

[datzenmike]

Was driving my '77 620 for 3 months- no problem. In fact, it was running great the whole time (I've only owned it for around 3 months). Drove it to a bike shop to do some quick business, killed it for maybe 20 min, then started it and took off. About a block and a half later, it sputters and dies. I could get it started with full choke but I had to floor it to keep it BARELY running....

 

...There's fuel in the sight glass of the carb so I'm guessing it's getting fuel. ...

 

... Oh- it's got electronic ignition. I'm not a mechanic- just a mildly informed tinkerer. Any thoughts?

 

Got it started with full choke.... Idle and possibly primary circuit plugged/partially plugged with dirt. Not getting enough fuel thus needs choke on to get started.

 

Carb could be full of fuel and still have the jet plugged

 

EI seldom goes wrong like points. Stick an old plug in one of the plug wires and ground to valve cover... crank and look for spark. Either there is or there isn't spark.

[moparvwfreak]

check spark. it almost sounds like what my passat and jetta are doing. and i knwo i am not getting much spark.

[tdaaj]

i'm with mike, i've delt with many plugged jets and thats what it sounds like.

[rover215]

thanks everyone-

I'll try giving it a bit of real petrol gas and see if it starts then. There is at least one vacuum hose that doesn't have anything plugged to it, but I think it was like that before. So I'll check that out, too, against my manuals. Yeah, I was getting spark just fine, and it did run (barely) with full choke, so I think the distributor shaft must be in tact. Probly wouldn't hurt to just pop the carb off for a good cleaning, either, so if the gas starts it, I'll definitely remove it and dunk it in carb cleaner- - good idea?

 

Will report back soon

[banzai510(hainz)]

if runs with choke pilled means to me that your bypassing the main barrel and getting it to run on the 2nd barrel. if fiing then ur elelctrical is more than likely good.

 

u could pull the oil gas filter and break it/cut it open to see whats in there??????? if nasty then youll have a higher chance of dirt in carb.webercarbsdirect.com sell DGV kits if needed.

 

 

olddatsuns.com ck it out!!!!!!!!!

[datzenmike]

Could also have suched water up from tank. It will settle to the bottom of the float chamber and partially block the jets. I've had this and it will clear if you can keep it going. A little methyl hydrate from wallmart paint dept $3.60 a literwill absorb it.

[rover215]

Well, I put a little gas directly into the carb (maybe 1/8 cup total) and it didn't fire; it just keeps turning over. Now it won't even start on full choke. In fact, after letting it die from pushing the choke back in I couldn't start it on full choke after that.

So pop the carb off and clean it? Getting impatient enough to have someone come out and (maybe) fix it- or at least diagnose it. I'm getting hot for a diesel again, so I'll probably get rid of the truck as soon as it gets going again.

[mike]

Is your distributor tight??? did you lose time or something???

[rover215]

I checked that and it seems tight; I can't wiggle it at all. It does sound more and more like timing, though, huh? These have timing chains, not belts, right? Could I have jumped a tooth?

[datzenmike]

Unlikely. Check for spark. If spark, check/ clean the plugs... they are likely wet or fouled by now. If the battery is charged it should start. If you get it to start you still should pull the carb and clean it and install a new filter to keep any crap from the tank from getting back in there. If the old filter is full of crap the tank is likely rusty.

[rover215]

... I replaced spark plugs, wires, distributor cap, and rotor- no change! Again, it turns over but won't start. It has a later model '70 or '80 dizzy on it. I got the right parts for it, so I'm still puzzled. I'm ready to unload it! Even though I'm sure it's something minor, I doubt I'll recover the cost of having someone come over to fix it, then sell it. What the heck?!

[mike]

Spark... gas... compression... Not running???? Did somebody put something in your exhaust?

[banzai510(hainz)]

pull coil wire place near chasisi and see if it sparks while starting.

 

watch this

or look up olddatsuns.com tech section

http://www.guba.com/general/search?query=hainz&set=5&x=0&y=0

[flinterman2000]

Interchange wires 2 and 3 and turn it over it should backfire through the carb. If it does not then you have a timing problem. The spark and the gas are not meeting at the correct time. Mike, do you think this could be it?:)

[Phlebmaster]

I found the thread...Matt I will get back to you later. :)

[whitechef]

I had a Dodge one time that died while I was driving it like I turned the key off. I screwed around with that thing all day messing with the points etc. Looked like it had good spark with the plugs laying on the valve cover and at the coil wire. The next day an old guy said to replace the coil, said sometimes they get weak. I did it and it popped off on the first crank and drove away.

[Roadracer Al]

See if there is a shear pin or woodruff key on the dizzy drive gear. It sounds like a timing problem.