403 not starting

[peterg]

Potential explination. The carbs are full of water and presumably an estimated 1/3 of the tank, hence the lack of petrol smell from the carbs!

[mikebro]

Originally Posted by peterg

Potential explination. The carbs are full of water and presumably an estimated 1/3 of the tank, hence the lack of petrol smell from the carbs!

That certainly explains it! And the tank doesn't have to have much water in it before the pickup pipe is seeing it. You will want to work out how the water got there in the first place too.

Mike
403-1402

[peterg]

The situation wasn't as dire as I thought. I believed that water sits on instead of under, as with oil.

You are right, it is amazing how little water is needed. The nice thing about an electric pump is that it pumps! I took a few samples and the water has dropped from about 15mm to very little but the petrol looks cloudy.

Now the engine runs but is a little rough (after embarrassing me at the top of the road, fortunately I could roll down the hill).

The water could only have got there from the petrol or condensation. Usually I fill the tank right up before leaving it to minimise condensation. Would putting E10 in help to reabsorb the water?

[AndrewA]

If it was me I'd drain it all and start again - the other option might be to fill it with the highest octane petrol you can get and see how you get on....

[AndrewSait]

Aplogies, only just seen this thread. If you have or suspect water in the fuel system there are products out there to cure this problem, e.g. Wynns Dry Fuel Water Dispersant.

I believe they work by emulsifying the water into the petrol.

Andy

[Geoff Kingston]

I have only just spotted this thread as well, years ago on a 403 I had in regular use commuting from Fishguard to Swansea at weekends I had a couple of breakdowns and had to call out the RAC who found water in the carbs, I changed garages but eventually found the problem a couple of small rust pin holes where the fuel filler pipe meets the base of the box it sits in, they were on the top and side of the pipe so in heavy rain some of the water that should have been going past the pipe to the drain in the corner of the box was getting into the petrol. Equally so you could have the same problem with holes anywhere around the base of the pipe especially if the rain water drain is blocked.
I cured the problem by cleaning up the whole of the outside of the base of the pipe where it is welded into the box and sealing it with Petro Patch.
Geoff.

[peterg]

Originally Posted by Geoff Kingston

I have only just spotted this thread as well, years ago on a 403 I had in regular use commuting from Fishguard to Swansea at weekends I had a couple of breakdowns and had to call out the RAC who found water in the carbs, I changed garages but eventually found the problem a couple of small rust pin holes where the fuel filler pipe meets the base of the box it sits in, they were on the top and side of the pipe so in heavy rain some of the water that should have been going past the pipe to the drain in the corner of the box was getting into the petrol. Equally so you could have the same problem with holes anywhere around the base of the pipe especially if the rain water drain is blocked.
I cured the problem by cleaning up the whole of the outside of the base of the pipe where it is welded into the box and sealing it with Petro Patch.
Geoff.

Not sure if that is the case but when I spilt some petrol I found that the drain pipe was blocked. Now cleaned out.

From a previous question I cured the gushing of petrol from the breather by adding a loop and a petrol filter as an 'expansion box' to the pipe.