Lotus Excel SE 1989 struggling to start

[BobH]

My Lotus excel has been struggling to accelerate under load especially uphills but has always started easily albeit using full choke. Today it would not start. I can hear the fuel pump but it is fast and and continues for at least a minute before it stops. I can smell fuel. Any thoughts as to whether this could be a stuck needle valve or another scenario. Any ideas welcome.

Thanks

Bob

[Sparky]

Could be a number of things, but I'd first check for hose damage upstream of the pump.

[EXCEL V8]

If it is a stuck needle valve don't forget that the fuel drips from the carbs onto the sparks below - the distributor!!  Beware!

Pete

[Escape]

As above, if you smell fuel and the pump takes long to pressurize, check for fuel leaks first! As a second, look for air leaks, those can cause both bad starting and a fuel smell.

If none can be found, you need to work through the system: good spark? correct fuel level in the bowls? nothing blocked in the carbs? timing correct?

You really shouldn't need full choke on any but the coldest days. And an Excel should have ample power even at lower revs. Maybe something has been not quite right for some time and has now gotten worse to the point the car is hard or impossible to start.

[BobH]

Ok. Thanks. I had planned to take it back to SJ sports cars, as Steve and Ross did the last service, but will need help locally now as I live in Jersey. The problem has been present for a few months now and as commented it has now become worse. Plugs are new. Spark present so will heed all advice and look further at the suggested possibilities.

Thanks

[ChrisJ]

I had a hesitation at 3000 rpm in 4th/5th, when it really stuttered when under load. Gerald (GST) though it was something breaking down under load. Once day it got really bad and I could hardly get up a hill I normally go up at 70 mph - finally managed to get to the top at 20 mph.

When it went to Gerald a couple of weeks later, he couldn't find anything apart from the possibility of bad fuel - and maybe a non OEM fuel pump (ticked really loudly). He replaced some of the fuel lines, fuel filters and installed a NOS Fuel pump. Been fine since.

I lived with the stuttering for about 6 months before it decided to try not to go up the hill.

[Escape]

If spark checks out, I'd look at fueling next. Easiest check is to see if the plugs are wet and smell of petrol after trying to start. You can also take off the cover off of one or both carbs to verify fuel level in the bowl. To check the pump, take off the feed hose to the carbs and put in a bottle while cranking the engine.

 

[BobH]

Will do thanks for advice 

[BobH]

Ok.

So I changed the four spark plugs, despite the previous ones being less than 9 months old. The car started on the 5th crank, albeit requiring some choke on this warm day. It seems to idle normally after cancelling the choke after a couple of minutes, but I still think it lacks power on acceleration and hills. The old plugs with thick black carbonised, smelling of fuel. Any thoughts - is this due to the fuel richness and the Dellorto Carbs.

[Escape]

Good that you have her running again! 👍 That will make it easier to get to a specialist and/or investigate further.

Blackened plugs do point to rich running, but that's not necessarily because of the carbs. If the ignition isn't in good condition, weak spark can lead to plugs soothing up quickly. Similar if the timing is off, with a running engine that is easy to check (if you have a strobe light).
Instead of the choke, try pumping the accelerator 3 times before cranking. If she fires, play a bit with the throttle and she should idle on her own soon enough. Less choke means less chance of fouling the plugs.

Did you rule out possible fuel leaks? If the smell is no longer there, I suspect she wasn't running on all 4 last time and it was unburnt fuel from the exhaust.

My Excel starting idling very badly some time ago. Other priorities kept her in storage for over a year, I then replaced the timing belt and of course reset the timing before trying her again. She's been starting and running good ever since, and got eve better after I recently had another look at both the timing and carb balance.

[BobH]

Thanks Filip. I had a new electronic ignition Ignitor kit with Flame thrower coil fitted 5 years ago and the guy who fitted does not think that is a problem as it either "works or doesn't". Distributor has new cap and rotor arm and HT leads are less than a year old, so will get the timing checked. The fuel smell has gone! 

Thanks