First time 620 owner - Getting things running

[Sonreir]

Hey, all. New member here.

 

Just picked up this 1974 620 last week. It's going to need a lot of work, but my immediate concern is getting it running. It's pretty difficult to start and will only idle for a short time (1-2 minutes) before dying and needing to be restarted.

 

The previous owner said they thing the problem might be with the EGR? It's been replaced, but maybe not hooked up correctly?

 

I've already gapped the points to .012" and tried to set the timing, but I couldn't get enough rotation on the dizzy to get things spot on. I'm at about 10° BTDC with the vacuum hose disconnected. I've got a Hot Spark electronic dizzy and coil on the way.

 

I have not yet checked compression, but it's on my to do list.

 

It appears I have an aftermarket carb. Any idea how to check the type and does anyone know what jetting I should be using?

 

Thanks in advance!

 

[datzenmike]

74 trucks were the first year with EGR so it's ... primitive. It's the round thing in the front of the carburetor just behind the distributor in your picture. Pull the hose off and put a suitable screw in the end to seal it up. This will deactivate it for now so we can get it running first.

 

That metal fuel line could be cut shorter so the hose doesn't have to bend and kink so much.

 

 

Points gap is 0.020" plus or minus a few thousandths.

 

The carburetor is most likely a 32/36 Weber and the jetting is close enough to get it running.

[banzai510(hainz)]

do not install the Hotspark yet!!!!!!!!!!!!!!!!!

 

what you mean you cant get the timming spot on.???????

If it 10dtdc and you still have lots of movement in the timing slot then you should be OK. If its crank all the way to the end of the timing slot to get 10 BTDC then something is off.

 

Vac advance hose on and off I notice myself don't make a difference but yes take it off when doing it.

 

 

I would change thew fuel filter

and when it stops idling. I would putll the airfilter and cycle the linakge to see if it squiorts gas when you cycled it. Means there is gas in the float bow(most likely)

If yes I then wouls clean out the idle jet or ck if dirty.

It might just mean it needs the idle mixture adjusted correct as when you first start up its still running on the choke. I cant tell if you have a manula or electric choke Weber and if electric you got a 12volt wire hooked up.

 

[Sonreir]

Yeah... the dizzy is cranked all the way to one side with no room left to go. I already gapped the points, but I'll double-check it. I'm used to old bikes and the procedure is a bit different, methinks.

 

Can/should I take some pics to help identify the carb?

[Sonreir]

I'm assuming I should be on cylinder one with the timing light?

[datzenmike]

The timing can only be set correctly when running.

 

You can get it close by setting TDC on the compression stroke. Both cylinder 1 valves should be closed. Timing mark on crankshaft at zero. Take distributor cap off and rotor shopuld be near the #1 plug wire above it.

 

 

Quote

Can/should I take some pics to help identify the carb?

 

It's a Weber, probably a 32/36. Take a picture where the throttle cable connects, could be a 38/38 but more likely 32/36. The jetting will be more than close enough to get running.

[banzai510(hainz)]

if you have the dist crank all to one side to get the 10deg I think there is a mismatch on the dizzy pedestal or oil pump spindal is off when someone reinstalled the motor.The Biggest Killer of a L motor. Misalignment!!!!!and no water in Rad poping headgaskets. Plus What does the oil light mean???WTF

 

there is a 8mm bolt under the dist one an loosen to get the timming plate more adjustment. and see if it gets better. but when running it goes out of time is what happens

 

But to know for sure one need to dial the motor up to TDC Zero on the crank and then pull the dist out and look how the spindal is clocked.

You got my vid to compare it!!

[Stoffregen Motorsports]

After you get it running, make sure those brake lines are good. Whoever bent them did a horrible job (no offense if it was you).

[banzai510(hainz)]

1 minute ago, Stoffregen Motorsports said:

After you get it running, make sure those brake lines are good. Whoever bent them did a horrible job (no offense if it was you).

that's what I thought

[Sonreir]

Yeah... brakes are definitely on the to do list. They seem lock pretty easy just going up the drive way.

[Sonreir]

OK... work today was replacing the ignition coil and old dizzy with Hot Spark.  Timing is much better and the intermittent spark I was getting is now all gone. I have it dialed in at 14° BTDC at idle.

 

Compression checks (done with a warm engine) are 120 PSI across the board (plus/minus one PSI) which are a little low for my liking, but good enough for now, I think?

 

Drove it up and down the road and it's definitely running better, but still down on power. Smells like it's running really rich.

 

Obligatory pics:

 

 

[Sonreir]

Also... anyone know what goes here? Is it a heater for the stock carb or something similar?

 

[]2eDeYe]

Yep, stock air heater tube to the air cleaner. 

[Stoffregen Motorsports]

How long has the truck been sitting? Does the engine have a lot of miles on it? You may benefit from an engine douche. Yes folks, you heard me right, engine douche.

 

Sounds like a commercial, but it's true. Add a quart of ATF to the engine oil and run it for a few hundred to 1000 miles. The detergent properties of the ATF can help loosen sticky rings, which may be one of the reasons your truck smells and "runs rich" and has low compression. The ATF can get behind the ring pack and clean out the ring lands making the rings float once again.

[banzai510(hainz)]

No power?

 

Is this a automatic?

 

if the distributor is in correct and valve are good and carb looks new make sure the choke plate is open when it warmed up
 

then check the cam timing when the crank is slowly turned up to Zero them look in between the cam hole and check the dash and the v mark on cam and see if it’s off by A lot.

[datzenmike]

1 hour ago, Stoffregen Motorsports said:

How long has the truck been sitting? Does the engine have a lot of miles on it? You may benefit from an engine douche. Yes folks, you heard me right, engine douche.

 

Sounds like a commercial, but it's true. Add a quart of ATF to the engine oil and run it for a few hundred to 1000 miles. The detergent properties of the ATF can help loosen sticky rings, which may be one of the reasons your truck smells and "runs rich" and has low compression. The ATF can get behind the ring pack and clean out the ring lands making the rings float once again.

 

Then switch to a diesel engine oil like Shell Rotella T4 it still has the higher ZDDP levels that are missing in today's oils AND diesel oils have higher levels of detergent in them.

[Sonreir]

1 hour ago, Stoffregen Motorsports said:

How long has the truck been sitting? Does the engine have a lot of miles on it? You may benefit from an engine douche. Yes folks, you heard me right, engine douche.

 

Sounds like a commercial, but it's true. Add a quart of ATF to the engine oil and run it for a few hundred to 1000 miles. The detergent properties of the ATF can help loosen sticky rings, which may be one of the reasons your truck smells and "runs rich" and has low compression. The ATF can get behind the ring pack and clean out the ring lands making the rings float once again.

Odometer is reading 60ish thousand. Not sure if it's been rolled over.

 

24 minutes ago, banzai510(hainz) said:

No power?

 

Is this a automatic?

 

if the distributor is in correct and valve are good and carb looks new make sure the choke plate is open when it warmed up
 

then check the cam timing when the crank is slowly turned up to Zero them look in between the cam hole and check the dash and the v mark on cam and see if it’s off by A lot.

 

Four speed manual.

 

I'm thinking carb issue at this point, but we'll see what my tinkering brings.

[datzenmike]

18 hours ago, Sonreir said:

Also... anyone know what goes here? Is it a heater for the stock carb or something similar?

 

 

The stock air cleaner has a vacuum operated flap on the snorkel and a temp sensor. It mixes outside and warmed air to keep the carburetor thinking it's 100F out all year long. Engine idles and runs smoother. Warm air cannot freeze and cause carburetor icing in the winter. Do you get freezing rain? fog and damp below 35F where you are? Perfect conditions for carburetor icing. I think wayno cut the bottom of a stock air filter so it would fit the Weber. 

[Sonreir]

OK.. I ran through the setup process (http://www.redlineweber.com/html/Tech/carburetor_set_up_and_lean_best_.htm?fbclid=IwAR3ZiVdMUKobmogKUvwpg-jQW6wefDOtuSnJoDUI8TNLOjGGB0XQnE4Dlrk) and I needed four full turns of the idle screw just to keep the engine running. The mixture screw didn't seem to do a darn thing. I tried it all the way in and four turns out and it didn't seem to affect anything.

 

I pulled the air filter and double-checked the choke and it seemed to be operating properly.

 

Also, might be unrelated, but the choke doesn't seem to do much when trying to start the vehicle (it'll start and idle about the same, with or without). Choke definitely stalls out the engine once warmed up, though.

 

Seems all signs are pointing to running really rich.

 

Does anyone have initial jetting recommendations or other things to try/check?

 

23 minutes ago, datzenmike said:

 

The stock air cleaner has a vacuum operated flap on the snorkel and a temp sensor. It mixes outside and warmed air to keep the carburetor thinking it's 100F out all year long. Engine idles and runs smoother. Warm air cannot freeze and cause carburetor icing in the winter. Do you get freezing rain? fog and damp below 35F where you are? Perfect conditions for carburetor icing. I think wayno cut the bottom of a stock air filter so it would fit the Weber. 

 

I'm in the Pacific Northwest, so we do see those conditions from time-to-time.

 

[620slodat]

7 hours ago, Sonreir said:

 

I'm in the Pacific Northwet, so we do see those conditions from time-to-time.

 

I modified the last sentence that you posted to your thread. It's not a typo. I live about 70 miles south of you along I-5, so I am very familiar with your weather. The only difference is that you have the wind from the Columbia Gorge that can at times create problems up there.

 

Don

[Sonreir]

A little more background....

 

I spoke to the previous owner and they were running this same setup for a while and the truck was their daily driver for a while.

 

On day on their way to work, the truck just bogged down and died. They pulled the carb and cleaned it, but no difference.

[banzai510(hainz)]

is the choke flap open after warmed up?

that carb looks kinda new to me and are very simple to figure out

 

fuel filter. maybe vy chance the fuel pump giving out. but tusallky they die a sudden death.

 

a cracked fuel line line MORE air in than fuel. Usaully its cracked right before the inlet

Edited June 15, 2020 by banzai510(hainz)

[Sonreir]

Just now, banzai510(hainz) said:

is the choke flap open after warmed up?

that carb looks kinda new to me and are very simple to figure out

 

Yes. I pulled the air filter and verified it was working.

[banzai510(hainz)]

do a Mexican tune up.

Rev the motor then put a rag over the carb and maybe it will suck the dirt thru. Or maybe pull the dirt out of the rag into the carb

 

sure your not running on 3 cylinders?

Edited June 15, 2020 by banzai510(hainz)

[Sonreir]

2 minutes ago, banzai510(hainz) said:

do a Mexican tune p.

Rev the motor then put a rag over the carb and maybe it will suck the dirt thru. Or maybe pull the dirt out of the rag into the carb

 

sure your not running on 3 cylinders?

 

Compression is 120 PSI on all four, and I just replaced the ignition coil and dizzy.

 

Strobe light on each plug wire would tell me if I'm getting spark, right? Anything else I could check to see if a cylinder wasn't firing?