521 dies under throttle

[raggmann]

1972 PL521

New plugs, wires are around 16ohms, new fuel filter, new fuel

Fires right up and idles decent

Burp the throttle and it'll rev up nicely

Try to drive it and it dies

Idle it in the driveway then mash the gas it revs up then dies like someone shut off the key

Any ideas what to check next?

 

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/th_DatsundiesI_zps03ef7c56.jpg

 

 

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/th_DatsundiesII_zps53da2007.jpg

[raggmann]

Yes it's the stock Hitachi

I don't want to spend the $700+ on a Weber 'till I know this thing will run

I'm about to the point of towing it out back and just filling it full of holes from a 12gauge, 270, or whatever

[datzenmike]

New direct replacement carbs are under $300. Includes everything and an air filter.

 

 

Check fuel level in front of carb. Should be at the line on the glass or close. Bet it's too low and you're running out faster than it can get in.

[raggmann]

Fuel bowl holds fuel at the line or slightly above actually.

To me it seems electrical but..........

 

I can roll an under hood video if that'd help.?.?.

[LenRobertson]

Some random ideas: How new/old is your coil? I've never experienced a bad coil myself, but have read here on Ratsun of that problem causing lots of weird happenings. Check all the connections at your coil and the wire going into the dizzy (assuming this is still points dist.). I had a Ford F100 where the wire from the points out through the body of the dist had broken or burned in two. Recently my L20b with matchbox was cutting out at speed just like the key turned off, then coming back to life. It turned out to be one of the spade connectors plugged into the matchbox was loose. I crimped it down with pliers to fix it. Try unplugging the wires from the back of the ignition switch and replugging. If you could hot wire a jumper wire from coil to points and it solves the problem then you would know it is wiring related (unless it is a bad coil). It has been years since I messed with points ignition, so I don't know if bad points or condenser could cause your problem. I don't thinks so , but just can't remember.

 

Len

[datzenmike]

Lem may be right. Sure sounds like running out of gas. But if lots of gas then could very well be electrical. 

[raggmann]

Lots of fuel

 

You can see here the fuel level doesn't vary

[ggzilla]

Idle it in the driveway then mash the gas it revs up then dies like someone shut off the key

Sounds electrical. A common problem is tighten the wires in the distributor and the coil and resistor.

[raggmann]

Cleaned & tightened all the spade connectors, etc.

Only thing I haven't done, as was suggested, is to clean the actual key switch.

[ggzilla]

Don't forget to inspect & tighten the non-spade connectors inside the distributor.

[raggmann]

Ok, got to doing some more investigating after work.

Figured I'd adjust the fuel level just 'cause.

Pulled the float and found the power valve (?) pin stuck in the up position.

Here's a couple shot of the parts truck carb I have torn apart

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/photo3_zpscb903c7a.jpg

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/photo2_zpsc76a663c.jpg

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/photo1_zps24eaede8.jpg

 

Got it freed up and seated.

I think it's a winner!!!

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/th_IMG_2495_zpsbd636575.jpg

 

Now I guess it's time to tear it down and re-seal the engine.

Do you think this is valve seals, head gasket, rings, or?

%5BIMG%5Dhttp://img.photobucket.com/albums/v294/raggmann/th_IMG_2499_zps0fa29002.jpg

 

Thanks again for the input all.

[ggzilla]

Congrats on solving the carburetor problem.

[ggzilla]

Why do you think the rings need replacing? Is the compression bad or the engine smoking?

[ggzilla]

Those are the main reasons for replacing rings

[raggmann]

Did the video(s) not work?

White smoke under acceleration. Very James Bond smoke screenish. Lol

[LenRobertson]

Good to hear you got the carb sorted out. I never heard of a stuck power valve but it is nice to know about, in case it ever happens to me . :lol:

 

When I hear "white smoke" I can only think of water/antifreeze going into a combustion chamber and out the tailpipe as steam. Either a bad head gasket or possible a leaky intake manifold gasket (if your particular intake has water running through it).  Does the white smoke have a sweet smell like antifreeze? There are all sorts of signs of a bad head gasket. That is one of them. When the gasket was going out on my L16, there was never water in the oil as some guys have. It just used an increasing amount of water over the weeks. Also, I could see bubbles in the water in the radiator when I would rev the engine up. But different gasket problems may have different symptoms. Probably time to do a compression test to see what that shows.

 

Len

[raggmann]

Thanks Len

Yeah, compression test is in order.

 

Did the video(s) work? I'm trying to figure out the new photobucket

 

Thanks again

[LenRobertson]

I meant to add to my previous post "I know this isn't what you want to hear" that you may have a bad head gasket. Maybe I'll be wrong, too. Yes the vids work fine, although I have a slowish internet connection and it takes a long time for them to load. It always seems to me even still pics on Photobucket load slow, but it could be my imagination. Oh, in the vid the smoke does look really white. Let us know what a compression test shows.

 

Len

[raggmann]

Did a compression test last night:

1-90 lbs

2-85 lbs

3-75 lbs

4-150 lbs

Thoughts?

Headgasket or rings?

It sat for 19 years so all the seals leak, thinking of pulling it out and do a re-seal but if it needs rings I'm ok with that.

[ggzilla]

Needs rings.

[raggmann]

Right on, winter project. Nice way to spend the -45 winter evenings-in the shop with the wood stove burning, drinkin' beer, and wrenching.