'74 400

71bigblock · Post by **71bigblock** » Thu Jan 29, 2009 12:19 am

Hi guys. Yesterday just brought home a '72 400 in great shape. 18xx miles.

Problem is, it doesnt run the greatest, if at all. Once it gets started, I drove around the yard once, no more than a minute and a half, and as I slowed down, it just bogged, and bogged, until it quit. I thought that maybe it was flooded out, but I pulled the plugs and they were dry. So I choke it, and pull and pull and pull and pull, and it doesnt start. If I open up the throttle and look in down the carb, it is full of vapors.

So I pull the plugs, turn it over a few times, put them back in, and it wants to start again.

I've cleaned the tank all out, new lines everywhere, the carb has been rebuilt, I've had it apart twice. Put a filter in-line. New plugs.

I'm kind of at a loss here. Where should I have the jets set? On the inside of the plastic cover it says a good starting point is one turn out on each, so thats where I have them. Any secret places in the carb I missed cleaning?

I've really only had it running for more than 5 seconds two or three times. I've pulled on it a few hundred I'm sure by now.

Back is sore

Thanks

JDT · Post by **JDT** » Thu Jan 29, 2009 1:31 am

Crank seals.....

DLDeere · Post by **DLDeere** » Thu Jan 29, 2009 1:59 am

Todd's probably right. It's always crank seals! They seem to be notorious for that! Look for greasy crud around the base of the engine and motor mounts, especially the clutch side. You should be able to see it from the front of the engine, even if the engine cover is still on.

Open up the jets another half turn and try. You maybe too lean once the engine warms up.

Lot's of secret places in the carb to clean. There's good info on this web site about the Walbro carb. Go to the home page and click on Technical Information. While you have the carb apart, double check the setting on the meter lever. When you pull a thin straight edge over it, it should just barely make contact. Since your plugs are dry, it could be the lever is too low, but don't get it set too high or you'll flood out all the time.

I'm playing with those CCW engines almost every night and these are a few things I have found to be problems.

JDT · Post by **JDT** » Thu Jan 29, 2009 2:11 am

Howard your list of sleds has grown some.

The VSA did not work out for you?

71bigblock · Post by **71bigblock** » Thu Jan 29, 2009 9:43 am

Ok, but wouldnt it not pump gas if the seals were bad? I forgot to say that it pumps gas just fine. And when it did run, it ran great!

I checked for buildup around the engine, and from what I can see, its nothing out of the ordinary for a almost 40 year old machine.

Sometimes it will be dry, and other times it will flood. I'm almost positive that its a carb problem. I'll check the tech stuff, probably take it apart again, and get back to you guys.

Post by **Matt** » Thu Jan 29, 2009 9:55 am

No, it can still have enough pressure to pump fuel, it doesn't take much.

There are lots of little pathways in the Walbro carb to clean out. As DLDeere said there is a Walbro tech manual in the Technical Info page of the main site.

Have you checked compression?

71bigblock · Post by **71bigblock** » Thu Jan 29, 2009 5:18 pm

No, but it must be pretty good, you can feel it in the recoil.

Good new though. I took the carb apart once more, really soaked it and cleaned it. Blew it out really well with the compressor. It runs good now! Still needs to be tuned, but it runs pretty darn good.

71bigblock · Post by **71bigblock** » Fri Jan 30, 2009 5:34 pm

Ok, new problem. I got the taillight/brake light to work, and the headlight. (The previous owner started jerry rigging, I finished

Whats the box under the dash on the left side? Mine starts to smoke now after 10-15 seconds of running. I looked up the wiring diagram, is it the rectifier, and can I just replace it, or is something causing it?

71bigblock · Post by **71bigblock** » Fri Jan 30, 2009 6:05 pm

It looks like you're right, and that I'm misinformed about my purchase. I looked up the '74 wiring diagram, that is correct. So I guess I have a '74. :green:

I'll give it a try

Rodimus Prime · Post by **Rodimus Prime** » Fri Jan 30, 2009 9:28 pm

no its just that most people have swapped out so many things on these sleds by now you have no idea what is original to sled and what isnt.

400brian · Post by **400brian** » Fri Jan 30, 2009 9:40 pm

'72s didn't use a voltage regulator.

But at any rate, look at the serial number on the side of the tunnel, A = '72, B = '73, C = '74, you get the idea.

Post by **Matt** » Fri Jan 30, 2009 10:24 pm

Go to the main page and look at "Models" - it has serial number listings by year and changes made each year.

71bigblock · Post by **71bigblock** » Fri Jan 30, 2009 11:11 pm

Yep, definitely a '74. So where is the best place to get one? No one around here has one. Dennis Kirk? Found a universal 1 wire one on DK for like $18.

Thanks

And another thing, mine is missing ski shocks, where can I get those?

Post by **Matt** » Fri Jan 30, 2009 11:22 pm

http://www.mfgsupply.com/m/c/01-091.html?id=tty83DQ9

71bigblock · Post by **71bigblock** » Fri Jan 30, 2009 11:32 pm

jdmatt wrote:http://www.mfgsupply.com/m/c/01-091.html?id=tty83DQ9

Yep, thats the same as the DK one.

Will those ski spreaders work? Or where can I get some?

lol, jeez, I'm full of questions.