Help, 510 not running good!

[gonzo]

This is my first dime and just got it not to long ago. Been doing a lot of reading here. According to the seller the stock carb was rebuilt but needed some work to get it running right. When I got around to checking the carb I noticed the choke was set to 3/4 closed (manual choke). After getting warm I tried setting at full open and it would stall. Played with and got it to idle but was real ruff and would run an the street. I then checked timing everything is we're it suppose to be 1st cyl TDC. Even the mark on the cam was right on. checked gat on point .020 and plugs at .032. Still same result. Got a rebuilt kit for another stock carb ( electric choke) got the same result. This morning did a valve check made some minor adjustment and checked compression also. 1-3 @ 170, 4@ 120. Started car again same problem. As the car was running I removed the wires on the Dizzy 1-3 car began to stall, on 4 it made very little change on idle. Switched plugs and cable with same resul!

 

So there's my problem car only want to run good with choke on an # 4 cyl is a bit weird. Any advice or help anybody has will be nice or do you guys think my engine is done?

[paradoxx]

I dont know if you checked it, but is the advance working or porperly connected? there has gotta be a vacuum line connected to the distribuitor, you can open it and suck the like to check of it moves. your sparkplug wires are silk or cable? are they properly connected on the distro cover? This is what I can think of now.

[gonzo]

There is a vacuum line from the carb to the Dizzy. When I suck on it there is movement. If the car is in idle and remove the line, it wants to stall. It seems to me that there is to much air going in. I sprayed carb cleaner around the carb, base and intake to see if there's suction but idle does not change at all. I've also changed fuel filter and set the float about half ways. Could it be the dual points distributor is bad? Will a electronic make that much of a difference? Am sort of running out of ideas.

[banzai510(hainz)]

got photos.

make sure the line going to the dist adv is from the carb not the intake manifold.

 

idle jet could be plugged that why you got to run the choke at idle.

or mixture scew out of adjustment.

ck the valve lash as a last resort also.

[gonzo]

i can get pics just let me know what need. it wont be for a few days cause i just got called out of town for work.

 

the vacuum is coming from the base of the actual carb. when i get back i will recheck the carb.

 

where do i find out about a Valve Lash?

[banzai510(hainz)]

I adjust the intake to .006 and exhaust .008 cold

 

You put a feeler gauge between the feeler gauge and the rocker arm when the lobe is up.

 

open the valve cover and rotate the 2 lobes cking 1 at a time when pointing up see if the rocker arm can wiggle a little bit. If yes then the valve is closing fully. then go to the next rocker on #4 cyl. If one is tight it could be the needed adjustment. If both are OK it could be a cracked piston or valve. or a few other things

[banzai510(hainz)]

what is does the timming light say?

[gonzo]

i did the vale adjustments cold and like you said .006/.008. i will let the car warm up try and drive it, check the valves next day see if it changed.

 

there is only 1 mark on my crank pullie, last i checked it was more or less on the mark. it was hard to keep it steady since the idle is so off and jumpy.

[datzenmike]

Three at 170 and one at 120 will cause a lumpy idle as #4 isn't doing it's job as shown by pulling the #4 wire off. Low compression can be several things including worn out or broken rings, damaged piston top, worn valve seat, damaged valve seat, bent valve, burnt valve blown head gasket. Not much you can do about these without removing the head. This leaves one thing left that you can do something about. Incorrect valve lash. If too tight it may not be closing and leaking compression.

 

Vacuum advance...

 

There should be NO vacuum advance at idle on an Hitachi carb so check where that hose is going. It should go to a port on the valve cover side near the base of the carb. If the idle is too high there will be a vacuum signal but at the proper idle speed there should be none.

 

Only running best with the choke partly on indicates it's running lean. Likely the primary jet is partly blocked as Hainz says.

 

there is only 1 mark on my crank pullie, last i checked it was more or less on the mark. it was hard to keep it steady since the idle is so off and jumpy.

 

The notch on the crank pulley should be at 12 degrees on the timing scale. (if you have vacuum on the vacuum advance hose disconnect it and plug the carb end or this will affect the setting)

 

 

Carb adjustment...

 

There are two adjustment screws, one for idle speed and one for air/fuel adjustment. On a warmed motor with choke off. Turn the idle mixture adjustment screw in or out to get the fastest smooth idle. Turn the idle speed down and adjust the mixture screw in until the idle quality drops, turn out until the idle quality drops and select a position about in the middle where it runs smoothest. Turn idle speed down and repeat until you cannot improve the idle quality. Be sure to set timing first for this.

[gonzo]

Thanks Datzenmike. I just got back home and re-checked the carb. There was actually a vacuum leak on the intake manifold that I temporarily block (dumd newbie mistake). I also noticed that the #4 cyl spark plug wasnt seating right so I tapped the hole and got it to seat better. Haven't done a compression test as its been raining here in L.A. Did some quick adjustment and it's seems a bit better, idle didn't change when I installed the air cleaner. Looks like a good sign! I will try and check it again tomorrow if weather permits.

[BOXIE]

I have experianced uneven idling be for with my GX1200.

 

The compression tester indicated more than 1 bar pressure diffrence between cylinders on the dry test.

 

So i added 3 squirts of new car oil on the pistons and it made no diffrence, so i confirmed it was the valves that wes not seating properly and had the haed overhalled and car is running like new.

 

Hope this helps

 

Boxie

 

 

[gonzo]

I tinkered with the car a bit today. I removed the the hose fittings on the intake and pluged them up also remove the spacer between carb and intake and installed a new gasket. I also swapped the dizzy with an electronic Sentra distributor.

 

I got it to idle with choke off but when I use the timming gun (w/o advance) my idle changes! I think my gun just took a $#!¥. When I test drove it the car kept jerking and when I let off the throttle it has small backfire's. I turned the distributor clock wise till idle got smoother but it's now way past the limit. When I drove it the response is better with almost no backfire at all, it still doesn't seem 100% though. Oh and it doesn't feel like it wants to turn off anymore when I hit the brakes hard.

 

I wonder if the timing chain has too much stretch? I still haven't checked compression since the minor repair, I'll try tomorrow morning, if still the same going to try the oil trick on #4. Might buy new plugs and wires just to be safe.

 

Running out of ideas. Just want to say thank again for everybody's help so far.

 

[banzai510(hainz)]

what does the timming gun say at idle????????????

 

 

I also swapped the dizzy with an electronic Sentra distributor.

 

A sentra dizzy will fit a L MOTOR IN A 510??????????????

 

 

make sure the vac adv is comming form the carb not the intake manifold to the dizzy

[gonzo]

what does the timming gun say at idle????????????

 

 

I also swapped the dizzy with an electronic Sentra distributor.

 

A sentra dizzy will fit a L MOTOR IN A 510??????????????

 

 

make sure the vac adv is comming form the carb not the intake manifold to the dizzy

 

Before i moved the timing i left it close to the single mark on the pulley which i believe someone said it was 12 btdc. every time i would use the timing gun the idle would change quite a bit even with the advance plugged at the carb. same thing with the old Points and new Electronic which is from a 1984 Sentra and seems to be working fine. as of right now, i have no idea were its at. moved clock wise so i believe its advanced. never tried that much on the Points but it was maxed out in the same direction.

[banzai510(hainz)]

I been workign on L series for 25years and never knew a Sentra distributor will fit a L series motor just by dropping it in there. I would LIKE TO SEE PHOTOS OF THIS!!!!!!!!!!!

 

Is car working OK now. or still bad?

 

if bad Im thinking a timming proplem either timming plate ,oil/distributor spindal off. I just see how a Sentra dizzy is going to work unless the top half is on a lower L series half and the timming plate is in the correct adjustmant.

[banzai510(hainz)]

OK I see this in the How to section and will read it. On How to Use a Sentra dizzy

[Spades]

I quickly read through this before I have to rush off to work, but did you check for vacuum leaks yet with starting fluid or propane? I am wondering if you have an air leak near the #4 cylinder...it is a long shot, but normally, if the car only wants to run well with the choke on, that indicates a lean condition...you may have multiple issues though, the whole thing may be running lean, and you notice it most on cylinder #4 because compression is lower.

 

If you have already checked for vacuum leaks with spray or another method, I apologize, I must have skipped over it. I am guessing that if air leaks are not a problem, you may have valve wear, most likely worse on #4 cylinder. normally a stretching timing chain will make it run like crap when you rev it up (as I learned on my first naps z motor)...but I doubt it will cause a problem that only shows up when you take the choke off and therefore introduce more air.

 

I would start with a caveman test of checking for any vacuum leaks below the carb going to the cylinder head, and then check the carburetor, and then check your fuel system to make sure your fuel pump is supplying enough fuel...most of the time when I see a car that won't run without a choke at the shop, it is due to air leaks or not enough fuel making it to or going through the carburetor.

[gonzo]

just got home and did a compression test. started with #4 and it read 120. put some motor oil in the spark plug hole and added some pipe tape (white stuff) to the threads of the compression tester and it read 150. checked the other cylinders and there still around 170. re-intalled the spark plugs with some tape on #4 and fired it. rechecked for air leaks with stater fluid around carb an intake with no change.

 

wonder what my next step should be since #4 cyl changed a bit! :confused:

[datzenmike]

Threads may have been stripped in the past.

[Spades]

I would guess worn threads on the lower compression issue. As far as you still having the problem but confirmed no air leaks, my question is if the fuel pump and carburetor are flowing enough. Does it run decent after idle and at Wide Open Throttle? Can you pull the air filter off and watch the secondary kick in? Did you check fuel flow to make sure that the pump is working properly and no fuel lines are clogged,ect. What is the fuel condition like? plenty of clean fuel?

 

I am suspecting that there is something going on with the carburetor or fuel at this point if it is still having the same choke symptom after setting the valves and timing multiple times and swapping ignition parts. I would suspect if there was a ignition misfire, the more fuel added from closing the choke would make the symptom worse rather than better. I suppose cam timing could be an issue, and I have seen cam timing make huge differences in idle, but may as well check fuel flow first since it is easier than tearing into the front cover to make sure something isn't a tooth off.

[banzai510(hainz)]

it is easier than tearing into the front cover to make sure something isn't a tooth off. ????

 

 

Just put to TDC and see if the rorotro is in the correct spot or rotor is pointing exactly at #1 plug that it. if yes then look at carb.

[banzai510(hainz)]

Jeff and I looked at a 510 wagona guy had and I cked out evertyhing and it was a bad idle situation also. I said this is EZ and looked at it I ck the timming ect.

 

Well months later theey did a compression ck and one cyl was bad and they open of the motor and piston had a hole in it.

 

I guess one could pull the crank case vent and open to atmosphere and see if its a stinky smell comming out at idle then you know you got a hole

[Spades]

he has done a compression check, it is ok except for a little low on cylinder #4, possibly from worn plug threads. As far as difficulty of checking the timing, I assume his engine is similar to the naps I have worked on, it may not be. On my napz, you cannot check the bottom crank to make sure the chain is lined up without pulling the cover. Checking the dizzy is easy by comparison, that is easy to see if it is a tooth off by lining up the cam and then checking to make sure the dizzy is pointed at #1...I meant checking the chain seems harder than pulling a fuel line and cranking the car over and seeing how much fuel is being pumped out and watching the carburetor to see if secondary is working,ect.

[gonzo]

Last nite i cleaned the threads on the plug and the head and put some gasket eliminator on. just to make sure it sealed, i let it sit over night. this morning i went ahead and double checked the valves

 

here it is set at the only Mark on the Pulley.

 

 

 

here are the two Marks together on the Cam Gear.

 

 

 

this is a top view of the cam. #1 looks to be in the right spot!

 

 

 

here you see were my Distributor is pointing and the fuel bowl at half full. notice the plug and no spacer on the carb.

 

 

you can see how much more past it i had to turn the distributor, but it points directly at my #1!

 

 

 

well all the valves were right on .006 intk/.008 exh. checked in the up position to be safe. then went ahead and started the car and let it warm up. made sure choke was completely of and adjusted the idle a bit. idle seemed better than yesterday! i did a full throttle acceleration from inside the car a few times and it sounded real good with a bit of black smoke but crisp. went to the carb and carefully looked down the secondary, gave it gas and didn't notice it open up. i manually pumped it and of course it wanted to shut-off. got it back to idle and after a few seconds idle changed and wanted to turn off. i gave it gas a few more times with same result, good idle then felt like it wanted to shut off, then back to idle (maybe about 5-6sec in-between) cranked up the speed idle a bit and took her around the block. she felt better than yesterday but a bit sluggish and full throttle. let it sit and idle for about a minute seemed good and didn't want to shut off.

 

 

it looks like slowly we been eliminating these small problems that been making the car run like crap. god knows what the previuse owner did to it. i wonder if it is my carb giving me issues now? i have a single Weber 40 DCOE that i want to rebuilt and install if i can find a used intake manifold. hopefully that helps.

[banzai510(hainz)]

What motor is this? L16/1820?????

 

Ok if you have a pulley with only one mark then its most likely a L18 or a L20 pulley.

What you have ais a L16 pointer on the front cover and a L16 using a 5 marks on the pulley set up as to time it.

 

Now I dont know if a stock L16 pointer comes out out correct using a l20 pulley or a prvious owner put that mark on there.But if correct the top chain sprocket looks timmed correctly to #3. it might not need to be #3 but it should work.

 

Now get your paint out again and where you have Zero marked put 5 more marks at say about 1/8 inch apart going to the right of the ORGINAL mark on your pulley. 0 , 5 10.15,20 degs.. This should be close enough for right now. This will be before TDC, TO FIRE THE DISTRIBUTOR

OR

You could find a later L20 sawthooth timming marker that bolts to the front cover. Just to let you know I have seen them on the right side also. so you would need the correct pulley if it was a right hand type. Now this can get confusing cause people slap differtn parts in a rush then say FUCK IT and run it till they sell it. Olddatsuns.com sHOWS this in one of the timming diagrams I think.

 

 

carb looks a little on the low side fuel wise but still might be OK, But dont they come with a fonolic spacer between the manifold and thee stock carb?????COULD THIS BE A PROPLEM??????

 

 

like before rev the motor to a high rpm and then put your hand over the main barrel to block that side and all the vaccum should go to the 2nd barrel of the carb. the 2nd barrel should open up momintarily. then you knw the vac 2ndary is not stuck.

 

 

also try running the car plugging the carb vac adv hole. try that and see how it runs

 

if leave the carb vac adv hose and look wht the pulley timming marks are doing as you rev it up. maybe the timming is go n backwards.