Square 4 reliability issue

[Dave Fearon]

Hi Everyone

I've had my SQ4 now for about 6 months and have had nothing but trouble. This is my first Ariel and probably my last! The engine keeps stopping whilst idling after a short run and takes ages before it will start again. I have checked the fuel tank breather, the filters on both the tank and carburettor. I have checked the float level and cleaned the the main jet and piston. I have changed the ignition switch but it keeps stopping! It will start after a while which would suggest fuel starvation but the float chamber is full. Any suggestions welcome. Thanks Dave

[simon.holyfield]

Yours is 1955, with an SU I think?

My thoughts:

• Is the coil failing? Any idea how old it is? Does it get warm?

• Is the condensor failing?

• Has anyone rewired the bike?

• Is the battery in good shape? I don't let mine sit around idling for long, as idling with a poorly charged battery will soon have it misfiring. I've actually fitted a battery monitor to mine

• Do you have a fuel filter fitted? Where? what type?

• Can we have a look at your rotor arm?

• How does it run, when it runs? It should be very smooth, with lots of torque, and it should start (and restart) very easily

• Have you had a look at the main jet? Is it oval? Can you compare the needle to a new one?

• What plugs are you using and what colour are they?

• Do you have a feel for the fuel consumption?

• Is the choke going fully off?

The other thing I am thinking about is the idle mixture. You can look at that on an SU by lifting the piston slightly and listening to the idle speed.

[JohnnyBeckett]

hi i find square 4 the most unreliable motorcycles i have had in the last 50 odd years they spend more time in the workshop than on the road they look nice and sound good when they are running right but it does not last long

[paul.jameson]

The Square Four is usually a pig to get right, but once you get it right, it is unbeatable for reliability, in my experience. I have done far more miles on Squares than any other Ariel model as a result. The Squares in question are /were 1936 OHC 4F 600, 1936 4G, 1948 4G, 1953 4GMk II, 1973 Healey 1000/4, 1975 Healey 1000/4 plus a few miles on a 1951 Mk 1.

[simon.holyfield]

As Paul says, mine always starts & goes well. You can ride it all day.

[dave.owen]

I'm with Paul on this , once set up correctly a great bike.once sorted just enjoy.

Dave

[nevhunter]

Don't forget these bikes are not new anymore and most have not had easy lives. A 4 cyl is 4 x 250s and all the bits are smaller and a few thou wear is more important than on a VB or such. Many have been monstered a bit and a good one is a credit to anyone who gets there unless you find the one that time forgot and only have to clean out the crankshaft galleries. Even that is a fair job. It's a motor that would benefit from a good oil filter and aircleaner. They are for people who like a bit of a challenge I feel. Smooth as.. Nev

[Dave Fearon]

Thanks to everyone for there support, reassurance and suggestions. I'm on a journey, when I have found the cause I will post it which may help someone else with a similar problem.

Dave

[dave.owen]

Dave , where do you live, there might be a sq4 owner close by to help.

Dave

[Simon.Gardiner]

...where do you live, there might be a sq4 owner close by to help.

Looks like you're both in Swindon!!

(Unless I'm very much mistaken Dave F is actually in the AOMCC , I've put him into the 'red names' to make this obvious to all.
Swindon Branch, to arms! )

SG