40 Minus, out of ideas

Canada_Tom · Post by **Canada_Tom** » Mon Jul 27, 2009 8:34 pm

Hello,
We're 4 university kids who are recently picked up a 40 minus, just what we needed to run the tender from shore to our mooring. It ran fine for a few trips there and back, but then when it really counted, no dice. From there it's been up to her when to start, everything from first pull to not starting at all. So we've worked our way through; checked the magneto, cleaned the points, made sure of the gap, got all the right readings and got a clean spark. Cleaned the tank, pipe cleaner through the hose, completely dismantled the carb (villiers) and cleaned everything we could. We found some silt in the bottom of the bell but managed to clean that out with a swish of gas and a clean q-tip.

We've been trying in a bin of water with the exhaust a few inches in the water and we checked the pin, we're running it at 10:1 as the FAQ says. As far as we're concerned, everything is checking out and should be firing up... but nothings happening.

Any thoughts would be greatly appreciated, we've just about run out of ideas to remedy.

- Tom

timberman2004 · Post by **timberman2004** » Mon Jul 27, 2009 10:42 pm

big hammer and a fairly vigorous thrashing ....

won't fix the 'gull, but by the gods you'll feel so much better afterwards

I recognise the frustration

phil · Post by **phil** » Wed Jul 29, 2009 10:37 am

Does the spark jump a 1/4"-5/16" gap with a strong blue spark? Sometimes it looks ok on the .020" plug gap, but doesn't do so well under cylinder compression. If not, clean points with silicon carbide sandpaper 320 grit or a proper points file, don't forget to use alcohol or acetone or laquer thinner to swab the points afterward. Gap at .020"
Ideally the carb should be cleaned using carb cleaner and compressed air, is the spark plug getting fuel on it when it refuses to start?

Post by **Charles uk** » Thu Jul 30, 2009 5:45 pm

Measure the compression & let us know what your getting, the compression tester will need an 18mm plug adapter.

Beware the carb cleaner if you've got a black carb, it will remove 50% of the paint.

All you need for ignition is fuel, compression & a spark all at the right time, something must be missing.

Waggles · Post by **Waggles** » Fri Jul 31, 2009 7:34 am

This sounds SO much like my 40+ when I first got it, traced it to a loose ignition backplate that was putting the timing out, sometimes the timing was near enough for the old dear to start, then it would go out while running usually at the worst possible moment with loads of people watching!

Make sure you can't move the backplate and that the locating screw underneath is correctly fitted and not loose.