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Robin Reliant engine running issues
sooty - 9/5/23 at 06:26 PM

The engine starts and runs rough. But left for 3/5mins start again and runs smooth.

But while cruising following traffic, its jumpy and cant make its mind to go or stop.

Changed Carb, Points and Plugs.

Any tips please to try and sort it.

Thanks

SteveWalker - 9/5/23 at 06:49 PM

I had some intermittent problems with my 2l Pinto engine. I tried plugs, coil, carb clean and refurbish, fuel pump swap - only to find that it was a kinked plastic fuel pipe, that was sometimes okay and sometimes moved just enough to close up the kink and reduce fuel flow.

coyoteboy - 10/5/23 at 11:54 AM

Too many things to guess. Check for tracking in the plug leads. Check for blocked fuel filter.

red22 - 10/5/23 at 03:14 PM

I had something like that in my case it was the low voltage wire to the coil making and breaking.

Not wanting to teach a granny to suck eggs but don't the reliants use an SU carb, is the dashpot full?

nick205 - 10/5/23 at 03:51 PM

quote:
Originally posted by coyoteboy
Check for blocked fuel filter.



This would be my next check as you've already checked/replaced a fair bit.

My 2.0 Pinto Indy suffered hesitation after fully rebuilt engine, fully serviced Weber carb (prefessionally jetted too), brand new fuel lines, plugs etc etc. Turned out to be crud in the little fuel filter on the fuel tank exit point. Renewed for less than a £5er and 30 mins and all was mighty again.

Always check the simple things and be sure.

rusty nuts - 10/5/23 at 04:02 PM

Start with the basics before spending any money. Check and adjust the valve clearances, tight tappets will cause all sorts of running issues, AFAIK the Reliant engine wasn’t made to run on unleaded (certainly the 750 and early 85 engines) so may suffer with valve sear recession? which will cause tight tappets . After adjusting the tappets is worth doing a compression test giving the engine full throttle when cranking, if low try a few squirts of oil down each plug hole and repeat test. Any large increase in compression will show worn rings. No mention of a condenser , distributor cap and rotor arm ? Check the fuel supply from the pump, pressure and flow. Has the dash pot being cleaned and topped up ? Mixture set? Any work been carried out on the engine? What fuel are you running? E10 might cause problems ?

Mr Whippy - 11/5/23 at 06:27 AM

Sounds fuel related. Have you taken the fuel pump apart to check if it is blocked? Most engines of that time have fine mesh screens which catch crap before the carb but block up quickly if the tank is rusty and starve your engine of fuel.