Any tips for starting 620 after sitting for 7 years?

[Crashtd420]

As far as the air box off, those lines are definitely a vacuum leak... just plug them temporarily.... or connect them and try to lean the air box to the side, or stick it back on.... 

And as far as it staying running that is dieseling... probably because the carb isn't adjusted right.... once you get the air/fuel screw and idle set right it should go away....

Is this a stock Hitachi carb?

Some one will probably correct me but usually the air fuel screw should be around 2 to 2 1/2 turns out.... the idle screw 1/2 a turn out from full closed turn up if idles to rough... work from there.... 

Usually you'll adjust the air fuel up or down and listen to the motor to find the spot where the idle rises then falls..  go back to the point where it was the highest then adjust your idle down....

 

[JohnnyBlaze]

8 minutes ago, Crashtd420 said:

As far as the air box off, those lines are definitely a vacuum leak... just plug them temporarily.... or connect them and try to lean the air box to the side, or stick it back on.... 

And as far as it staying running that is dieseling... probably because the carb isn't adjusted right.... once you get the air/fuel screw and idle set right it should go away....

Is this a stock Hitachi carb?

Some one will probably correct me but usually the air fuel screw should be around 2 to 2 1/2 turns out.... the idle screw 1/2 a turn out from full closed turn up if idles to rough... work from there.... 

Usually you'll adjust the air fuel up or down and listen to the motor to find the spot where the idle rises then falls..  go back to the point where it was the highest then adjust your idle down....

 

I started to put the air cleaner back on, but ran out of light. I’ll try to get that all hooked up tomorrow and start it to see if any improvement to idle. It is the stock carb. I turned the adjustment screws and they made no difference in idle, so I turned them back to where they were. I guess with the air cleaner off those vacuum leaks are creating too many issues for the adjustment screws to make a difference, but idk. Making adjustments with the air cleaner on seems like it could be difficult. Do most people take it off and plug the holes or just lean it over with everything still connected? Ofcourse the heavily dry rotted air cleaner gasket doesn’t make for easy removal and installation on the carb. 

[datzenmike]

Shine a flash light down both barrels. Make sure the secondary, the one farthest from the valve cover, is closed. Now check that the primary is closed or close to closed. Open and close the throttle while watching it to see how it operates. It should close on the idle speed screw that hold it open just enough to idle.... does it?

 

 

[JohnnyBlaze]

12 hours ago, datzenmike said:

Shine a flash light down both barrels. Make sure the secondary, the one farthest from the valve cover, is closed. Now check that the primary is closed or close to closed. Open and close the throttle while watching it to see how it operates. It should close on the idle speed screw that hold it open just enough to idle.... does it?

 

 

I will double check today when I get home, but I do know the secondary cover is closed and I believe the primary is closed also.  The upper primary cover(choke one) is open an 1/8"-1/4", but doesn't close once the engine warms up like I think it's supposed to do.  I am going to put the air cleaner back on today and try it since with it removed all of those hoses are open and maybe creating a vacuum problem.  I'm not sure if that's the problem.  I would think with that off it shouldn't make it run too bad because it's not easy to work on the carb with it attached and I figured most people would make adjustments with it off...or am I wrong?  Thanks

[datzenmike]

Choke plate should be closed to start when cold. The restriction increases suction and draws more gas in to run richer during warm up. In addition the fast idle should be engaged. Choke should open gradually over 5-10 min depending how cold it is. If the choke doesn't open the fast idle may stay on causing a very fast idle. 

 

Try holding the choke plate open and give a small rev with the throttle and see if it drops down.

[Stoffregen Motorsports]

Good call on the head re-torque. That may help with the leaky gasket.

 

I wonder if corrosion in the carb is causing the throttle shaft to stick. If it got any water down the barrel, or mouse pee, that can cause enough corrosion to make it stick.

 

Seven years sitting is a long time and in my experience (here in NorCal), it is the limit. Every car or truck I have ever resurrected that sat for seven years needed to have the entire brake hydraulic system rebuilt. All of the hoses, the calipers, wheel cylinders and the master cylinder. If one or more of the wheel cylinders went bad while sitting, it could have soaked the brake shoes with brake fluid, meaning the shoes will need to be replaced too. While the hoses are off and the master cylinder is out, that's the time to blow out the hard lines.

 

It may be coincidental, but seven seems to be the magic number. I've tried to cheat it and it has always come back to bite me in the ass. Three times I've had brake parts fail after that magic seven year mark. It's scary to lose brakes due to a popped wheel cylinder or even worse, a popped master cylinder.

[JohnnyBlaze]

2 hours ago, datzenmike said:

Choke plate should be closed to start when cold. The restriction increases suction and draws more gas in to run richer during warm up. In addition the fast idle should be engaged. Choke should open gradually over 5-10 min depending how cold it is. If the choke doesn't open the fast idle may stay on causing a very fast idle. 

 

Try holding the choke plate open and give a small rev with the throttle and see if it drops down.

It's been in the 50s-60s here and the choke plate is closed before starting then immediately opens an 1/8"-1/4" when started and doesn't seems to open any more as it runs longer.  I will try to adjust the idle speed screw out to see if that helps any, but when I did turn it yesterday about 6 turns in both directions it didn't make any change...maybe I didn't turn it enough.  I haven't really gotten a definitive answer, but maybe hooking the air cleaner up with help the idle speed too.  I'll up when I get home.

[JohnnyBlaze]

1 hour ago, Stoffregen Motorsports said:

Good call on the head re-torque. That may help with the leaky gasket.

 

I wonder if corrosion in the carb is causing the throttle shaft to stick. If it got any water down the barrel, or mouse pee, that can cause enough corrosion to make it stick.

 

Seven years sitting is a long time and in my experience (here in NorCal), it is the limit. Every car or truck I have ever resurrected that sat for seven years needed to have the entire brake hydraulic system rebuilt. All of the hoses, the calipers, wheel cylinders and the master cylinder. If one or more of the wheel cylinders went bad while sitting, it could have soaked the brake shoes with brake fluid, meaning the shoes will need to be replaced too. While the hoses are off and the master cylinder is out, that's the time to blow out the hard lines.

 

It may be coincidental, but seven seems to be the magic number. I've tried to cheat it and it has always come back to bite me in the ass. Three times I've had brake parts fail after that magic seven year mark. It's scary to lose brakes due to a popped wheel cylinder or even worse, a popped master cylinder.

One of my next tasks after the idle issue is to address the clutch and brakes.  Both brake and clutch masters have no fluid in them except maybe a little in the bottom.  I don't think the e-brake works(probably stuck) and I'm sure the pads, rotors, shoes, and drums and maybe more are old and crusty.  I was trying to decide if I should just replace all of those brake parts as well as the calipers, wheel cylinders, hoses, brake and clutch masters before even trying to get them working.  Or I could just add fluid and spray everything with brake cleaner and see what happens.

[banzai510(hainz)]

take a photo of the carb.

I seen people hook the vavuum advance to the manifold instead of the carb.

 

As ofr the leaking head gasket. its not a huge issue yet as I run them like that

Edited October 24, 2018 by banzai510(hainz)

[JohnnyBlaze]

1 hour ago, banzai510(hainz) said:

take a photo of the carb.

I seen people hook the vavuum advance to the manifold instead of the carb.

 

As ofr the leaking head gasket. its not a huge issue yet as I run them like that your awhile when I get a Datsun.  My 510 has this but too lazy to 

So apparently the engine doesn’t like the air cleaner off. I hooked back up and the idle is much lower. I unhooked the one vacuum hose that closest to the carb that doesn’t have a clip on it and the idle went high again. I guess that solves that issue. My question is now...does everyone make adjustments to their carb with the air cleaner installed or what? Doesn’t leave a lot of room. 

 

[wayno]

Plug that hose with a small bolt or something when you take the air clear off.

[datzenmike]

The choke should open completely.

 

When warmed up HOLD it open and give a rev and the fast idle cam may drop and the idle lower.

[Stoffregen Motorsports]

21 hours ago, JohnnyBlaze said:

I was trying to decide if I should just replace all of those brake parts as well as the calipers, wheel cylinders, hoses, brake and clutch masters before even trying to get them working.  Or I could just add fluid and spray everything with brake cleaner and see what happens.

That's the gamble. I am sure you could get the brake system working with a little work and maybe only a couple parts, but that's what I was warning against. You may get it all working, but then blow a seal in one of your calipers or whatever. Hydraulic seals are usually binary, they work until they don't.

 

Especially now that you've found both master cylinders dry. That's a telltale sign that seals have gone bad.

[JohnnyBlaze]

20 hours ago, Stoffregen Motorsports said:

That's the gamble. I am sure you could get the brake system working with a little work and maybe only a couple parts, but that's what I was warning against. You may get it all working, but then blow a seal in one of your calipers or whatever. Hydraulic seals are usually binary, they work until they don't.

 

Especially now that you've found both master cylinders dry. That's a telltale sign that seals have gone bad.

I'll probably just replace most of brake components since it's all old and been sitting a while.  That way I don't have any sudden failures.  I added fluid to the clutch master and the slave cylinder isn't moving and the shaft has rust on it, so I'll replace both of those too.

[JohnnyBlaze]

I torqued the head studs and most were tight. Maybe 1 or two budged a tiny bit, so we’ll see. My new 3 row aluminum radiator from Radiator Expressed came today, so I removed the old one. Went to install the new one and the mounting holes do not match up at all ?. It is taller than the factory one, but that may not be an issue. I called customer service and I’m supposed to hear back from them after the technical department looks into it. There isn’t even material on the radiator in the areas that match up with the mounting points on the truck or I could just drill holes in that area and bolt it up. I don’t want to drill new holes in the truck because they won’t be threaded. Always something ?.

[datzenmike]

To re-torque the head bolts, first loosen a couple of turns then tighten to 60 ft lbs. Make sure you only have one bolt at a time loose and then tighten. Any order.

 

I find the steel bolts tend to stick or 'freeze' to the block threads and it takes way more torque to loosen them than what they were set at originally.

[Stoffregen Motorsports]

Yes, you need to loosen and re-torque the head bolts, one at a time. 

[JohnnyBlaze]

Ok, I will loosen and re-torque the head studs.  I didn't even think about having to do that since I've never had to try to re-torque anything.

 

Thanks

[Stoffregen Motorsports]

Use the proper sequence, starting in the middle.

 

Be careful of them sticking. If they feel like they may be stuck, you may have a rusty head bolt and if it's too rusty, it can break.

 

[JohnnyBlaze]

Well I re-torqued the head studs and as for now the head gasket is not leaking.  I installed the new radiator and had the truck running for a while and no sign of leaking from the head gasket like before ?.

 

I removed the bed today also and noticed the fuel tank hoses were dry and one cracked.  2 of the hoses are a different type of hose than the rest of the black rubber hoses.  They are a harder plastic/rubber and one cracked in half.  I can replace them with the same black hoses I have replaced the others with, but I didn't know if they are supposed to be made of something different for a reason.  There looks to be a inline fuel filter in one of the hoses I am talking about, so I guess I should replace that too.  Does anyone know anything about these thinner hoses that attached to the filler pipe by a circular hard line?

 

 

[datzenmike]

Not a filter, that's up front just before the fuel pump. What you're seeing is a check valve to prevent gas leaking out the vent hose in a roll over.

[JohnnyBlaze]

5 minutes ago, datzenmike said:

Not a filter, that's up front just before the fuel pump. What you're seeing is a check valve to prevent gas leaking out the vent hose in a roll over.

Ah that makes sense. I know the filter under the hood, just didn’t know if that was another small one. Do you know if those different hoses can be replaced with regular fuel hose or are they something different/special? Thanks!

[Stoffregen Motorsports]

Any fuel spec'd hose will work. It's likely the red-ish hoses in your pic are not fuel spec.

[JohnnyBlaze]

I started to replace the clutch master, slave cylinder, and hose. I think my clutch is frozen/rusted together. I new the clutch wasn’t working, but I assumed it was due to the slave being frozen. When removing the old slave cylinder I noticed the clutch fork barely moves...basically only wiggles a little. I have the new clutch master in and will have the hose and slave installed in the morning. Any tips for getting the clutch/clutch fork unstuck? I’m going to have to add fluid and bleed the system first, but not sure how easy that will be with a frozen clutch. 

[datzenmike]

I'm not convinced the arm is stuck at all. Takes a lot of force to move it back.