Zenith 361V Blocked

[neophyteguy]

I'm back in Oz for a few weeks and have been driving my 1971 Series IIA-Ex Mil 109. It started like a champ and I have been driving it regularly for the last couple of weeks.

Coming up the hill this afternoon and it coughed and sputtered, then cut off. I stopped and noticed there wasnt any fuel in the filter. I took off the hose between the filter and the carby, blew through both the hose and the filter and all seemed fine. I also manually pumped the fuel filter and had plenty of fuel coming out of the hose when it wasnt connected to the carby.

Then I put my lips on the carby and tried to blow through it.......NO GO!

I'm a bit handicapped at the moment as my manuals aren't here with me-but I do have internet access and my buddy (thanks LV) has posted up the LR manual there for me.

I really don't have any idea how to clean the jets or the bowl, which I believe is my next step. Any help is greatly appreciated!

Cheers,
Neo

[neophyteguy]

SORTED!

I squirted some WD-40 into the inlet on the carby and let that sit for a few minutes. I then connected an old 12V sprayer pump I have to a piece of hose and connected it to the inlet. I put ( I think!) some air through the carby and when I disconnected the pump and blew through the inlet. I was then able to hear a small bit of air. Once I connected everything back up, it fired up like a champ...............

Also, as this vehicle sits for up to 6 months (I live overseas currently), what is the best way to ensure the fuel doesn't go bad and that I minimise water in the petrol? In one of the other threads someone mentioned a water filter. Does anyone have an example of this or a web link?

Cheers,
Neo

[chazza]

If you can easily disconnect the suction side of the fuel pump you could run the engine (before storing it) until the carbie runs dry. An inline tap might work as well.

I am guessing that the the alcohol in modern fuel has attracted water, which has caused some white fluffy corrosion somewhere in your carbie and blocked a jet, or stuck the float needle,

Cheers Charlie

[JDNSW]

You need to at least partly disassemble the carburetter. Easier to do on the bench, but can be done on the vehicle.

Disconnect the fuel line, and the links between the throttle and the upper part of the carburetter, and note how they went together and which hole was used in the accelerator pump lever (photos help).

Then undo the screws holding the top cover on and remove it. Remove the float by sliding the pin out, careful not to lose the needle valve (always note how it went together).

The emulsion block can then be removed from the top cover by undoing the needle valve seat and two screws. All the jets can then be removed and checked.

I expect you will find a collection of corrosion products in the bottom of the float bowl, some of which will be blocking jets or possibly passages in the emulsion block (in my experience the slow running jet is the one that blocks) . This is where having the carburetter off helps, but it is not absolutely necessary. Bowl does need to be clean though.

Reassemble, preferably with a new gasket and O-Ring. While you are at it, you might want to check the top cover for flatness and skim it if necessary, although this means removing the rest of the bits from the top cover.

Hope this helps,

John

John

[incisor]

penrite make a fuel preservative that you add to a tank and it will last for a year or more...

[Blknight.aus]

to prevent the problem from occouring, shut the vehicle down let it go cold, disconnect the fuel line from the carby and then (with the fuel line blocked or routed back to tank) start the engine and run the engine till the carby runs out of fuel.

if its going to have a really prolonged stop I'll drain the fuel tank and seal it up then disconnect the fuel line dunk it into a bottle of metho and run the engine till it stops on the metho then purge the fuel line before reassembling the fuel lines.

[neophyteguy]

Firstly, thanks you all for your help in this matter! You guys really are a wealth of knowldege...........

After having gotten the carby to work, without taking it off the car and by putting a bit of air through it, I went back to work in the paddock. No problems, just back and forth from the shed to where I was working. Then I got a bit "off track" and the truck got into a slightly bonnet down/left side lower position. The vehicle then cut off and wouldn't restart. Popped the bonnet and sure enough the fuel filter was dry. Popped off the filter, blew through the carby and was not able to blow any air through. However, there was certainly fuel in the inlet side of the filter which was pressurised and was trying to get past the filter and into the carb.

I've now taken the carb off and blown through anything I could find (jets, etc.) with a modified bike pump as no high pressure air was available. What I did realise was that the symptoms I was getting of not being able to blow through the inlet hose was that the needle valve was engaged. It seems to be functioning well now as I tested it when I had the carby opened up.

Also, there was a fair bit of fuel in the carby when I took it off, so I guess it is possible that there was fuel in the bowl which had engaged the needle valve.

I'm going to put the carby back on in a bit and was wondering if I need to do anything before I put the carby back on.

It was rebuilt less than 2 years ago and has less than 3000 km's on it. The bowl was perfectly clean as was the entire inside of the carby.

Any thoughts?
Cheers-JRW

[neophyteguy]

I've just disassembled the carb again and blown through everything I could with a high pressure hose. I took out all the jets, blew through them as well as any channels I could find.

Still no joy!

The bowl is definitely filling up with fuel as the needle valve is actuating and the bowl was full of petrol the last time I took the top section off.

Any thoughts?

Cheers,
JRW

[Timj]

Usually you can tell if there is fuel getting in by pumping the accelerator or throttle linkage while looking down the carbie (engine off). There should be petrol spraying into the carbie from the accelerator pump. If there is then you should be able to start the car as long as you keep pumping the accelerator. If you can but it then dies when trying to idle you have blocked jets or passages, if it won't even start but you know that the pump is putting petrol in to it then you have some other problem like distributor or coil. Coil can exhibit issues like stopping on particular slopes.

TimJ.

[neophyteguy]

Thanks Tim!

I've managed to get it started a couple of times now and have managed to get it back up to the shed--mostly by being towed!

It has started a couple of times after keeping it turning over. It then runs like a clock as it idles. Then it just seems to stop. Instantly...........

When I took it apart earlier, I blew air through everything that was a hole, had a hole in it or even looked like it should have a hole. I'm pretty comfortable that I have blown out any gunk that may have been in there.

I am definitely getting spark from the plug wire when held against the block.

Cheers,
JRW

[Timj]

Hmm... not really sure, perhaps a vacuum leak that takes the car getting warm before it happens? Something like a warped top on the carbie? That one is fairly common. Check timing, rev the car to make sure it moves with mechanical and vacuum advance, take off the vacuum advance to the dizzy and block it to set the timing and then see if it changes when you put it back on. Unfortunately there are a lot of possibilities despite the fact that it is a very simple engine setup :). The coil on one of mine was getting very hot and the car would start and run for ages, but if you then turned it off it would not start again until everything cooled down. Changed the coil and away it went again.

Sorry, not sure if that helps a lot.

TimJ.

[chazza]

I agree with Tim about looking for a spray of fuel in the carburettor throat when the accelerator is depressed.

If there is fuel there substitute a known good coil,

Cheers Charlie

[wagoo]

An old motor bike trick I use that rarely fails for me to clear blocked carby jets, if you can get the engine started at all is to remove air filter hose from carb, slowly build engine revs up by manipulating the throttle linkage by hand, and when the engine won't rev any faster block the top of the carb with your other hand with the throttle wide open. The engine wants to suck 2.28 litres of something every second revolution, if you block off the air supply it will try to pull it through the jets of the carb. Just before engine stops from overfuelling take your hand off the carb top and repeat procedure until engine runs normally. Speaking of normal. Zenith carburator castings dont get normalised (stress releived) prior to machining during manufacture.What happens is that they get normalised and distort with the repeated heating and cooling of the engine in service, which leads to overfuelling. To restore the carb it should be completely dismantled and all flat surfaces dressed by rubbing them on a sheet of wet and dry paper placed on a smooth flat surface or a sheet of glass. Once done they generally don't distort again.
Wagoo.