Lotus Elan and Lotus Elan Plus 2 Forums

I just bought a Plus 2 Federal via the internet, which I'll NEVER do again. I won't go into all the utterances I've let fly the past few days, but needless to say, I'm not a happy fellow.

The car I bought was advertised as a runner.. the seller said, starts, runs, stops.. may need to just jump the battery.

I was delivered just last week. The list of items not working is longer than this post will allow in number of characters.

I have the Zenith Stromberg Federal carbs. I posted in the 'introduce yourself' area a few days back that I would be rebuilding them. I should say I work on SU carbs on all my Triumphs, and once you get them adjusted, I love them.

I was hoping this ZS carb would be the same.

I received two rebuild kits from R.D Enterprises Friday. I rebuilt both on Saturday. I have the 4 inch thick owners manual, the Haynes Zenith book, and I"ve read these forums for hours. I should add that I discovered the secondary butterflies were removed and the crossover tubes blocked. After being told on this forum that most prefer to do so, I felt relieved.

So my concern is, where is there any adjustment on these carbs? The lower brass piece under the float bowl doesn't allow any jet adjustment. The needles don't have any adjustment either. (B1G needles). The car will start and idle, but that's it. Add any throttle and it will stutter and fail. I've measured the jet at 2.75mm below the bridge. That does not allow any movement, it appears set and rigid. I've tried to move the needle ever so slightly in and out of the air valve cylinder, exposing the needle base proud of the bottom of the cylinder, but nothing changes.

I can't tell if I'm rich, or lean.. but I'm smelling rich from the exhaust, but when I put my hand down by exhaust, I'm not getting any wetness. If I attempt to raise the cylinder/piston or whatever the real term is with a screwdriver, (although it's impossible to attempt the 1/32nd inch to see if it revs slightly, then settles, or revs and stays reved, or just starts to fall off.. but no way can I get that to indicate anything at this point.

A non-adjustable carb? How is that possible, or am I missing anything? CD175 carbs. Experience and guidance needed. I've had this car in my garage for 5 days now and the wife parked out on the driveway.. with temps getting down to -2F on Saturday.. there will be no 'happy wife, happy life.'

I obviously an not in a position to make drastic changes, so what am I to do?

I won't even mention that I'm chasing electrical issues, no gauges working except AMP meter, no Tach, no oil pressure gauge working, no engine water temp gauge working. This car is breaking my spirit. I've always loved the analytical challenges these British cars present, but I've never been so frustrated with a car like I am now.

Sorry, I need to vent some frustration... what am I to do next with these carbs?

I'm off to the Whiskey cabinet, I'm mentally beat.

Thanks in advance to all who are inclined to offer help/advice.

If your lucky, Lotus only turns you to drink.
We have lost more fine folk here than you can count.

Be well

https://www.buckeyetriumphs.org/carburetors

A great series that really helps with these carbs.

How is your fuel flow? electric or mechanical pump? tested off the carbs to see how much flow and pressure you're getting?

For the electrical woes, start by going through every Earth in the car and make double-damn sure that they're all good. Lotus electrics live and die by their Earths.

If I recall correctly the emissions Stromberg carburetors sold in the US had no adjustment originally. I believe you can modify the the pistons to allow needle adjustment but its been 30 years since I worked on a Stromberg headed car. The other area to check is the choke and temperature compensator as these could be faulty and upsetting the mixture as well as the pump pressure and fuel level in the bowls.

Given that the car appears to have been "maintained" ( and I use the term loosely) by people with the mechanical skill of monkeys anything could be wrong

cheers
Rohan

There was no mixture adjustment on the ZS carbs used on the elan
Ian

SENC wrote:https://www.buckeyetriumphs.org/carburetors


How is your fuel flow? electric or mechanical pump? tested off the carbs to see how much flow and pressure you're getting?

Mechanical fuel pump. a fuel filter was plumbed in just prior to the fuel pump. I have a new replacement for that and will add it today.

The Veg wrote:For the electrical woes, start by going through every Earth in the car and make double-damn sure that they're all good. Lotus electrics live and die by their Earth's.

I am replacing the two braided grounds on either side of the engine. One appears to cross from top to bottom of engine mount? the other side it appears to ground engine to chassis.

I wire brushed the ground point in the center of the boot where the negative battery cable attaches.

Are there any others that I'm not seeing? I have the factory manual with the Federal +2 wire diagram, but that is a challenge for me.

The PO created an electrical nightmare for me, there are wire crimps and terminations all over. Sorting this out won't be easy.. I'll start with the grounding straps and replacing the voltage stabilizer. we'll see how it goes from there.

rgh0 wrote:If I recall correctly the emissions Stromberg carburetors sold in the US had no adjustment originally. I believe you can modify the the pistons to allow needle adjustment but its been 30 years since I worked on a Stromberg headed car. The other area to check is the choke and temperature compensator as these could be faulty and upsetting the mixture as well as the pump pressure and fuel level in the bowls.

Given that the car appears to have been "maintained" ( and I use the term loosely) by people with the mechanical skill of monkeys anything could be wrong

cheers
Rohan

Rohan: SENC sent me a link to Buckeye Triumphs where there is an article that shows the steps to drill out the pistons etc to fit adjustable needles.. but I'm not quite sure I can pull that off.

The choke cable is not connected as the retaining piece on the carb to hold the end of the cable was missing. I have the choke cams backed off so they aren't in play, or so to my thinking anyway.

I don't know the pump pressure as was suggested by SENC as well. I don't know how to work that out. On one of my Triumphs that has SU's I have a fuel meter plumbed in just prior to the carbs to make sure I'm under 3lbs of pressure. For this Lotus, one of the floats was really out of spec prior to my rebuild. I'm confident I have the floats both set properly now.

the temperature compensator, I removed from both carbs, tested that they were not stuck, replace the inner and outer 0 ring gasket things, and reinstalled. I'm not sure what else to do there.

Of note: the 'idle trimmer screw' is fully seated.

The diaphragms in both by-pass valves were good. However as I removed the adjustment brass part to replace the o-ring at the outer most end, the device that applies tension to the springs, I didn't preserve the amount of tension or position of the spring seat. I don't know how to properly set those. I currently have them set fully counter-clockwise which I believe puts the maximum force on the springs/diaphragms. Advice there welcome.

I read a quote from Chapman talking about why they didn't make the rear suspension adjustable,
"They'd only cock it up!"
That was the thinking behind the non adjustable carbs. Nevertheless, people won't leave them alone. Mine is not a plus 2 and is a '69 so maybe different. There are several factory adjusted pieces that now need to be checked, the book should tell you. Also, the needle type should be checked and is it properly placed, some were spring loaded. Is the damper spring the correct one. Mine has a little plastic valve separate form the body to retard the spark on overrun. They are no longer available and if yours is missing are the three vacuum connections plugged? Just go slow SZ are like SUs only different!

99% of carb problems are electrical

Agree. One common cause of poor running is goosed HT leads/cap

Hi,
Earths for instruments and other bits inide the cabin are bunched together at the rear of the dash panel where it meets the gearbox tunnel. A difficult place to tighten the nut so just temporary sting a wire from there to the engine and see if that helps the instruments to work.
Tony

& check your timing. They didn’t say it ran well or great did they?

10kph wrote:Hi,
Earths for instruments and other bits inide the cabin are bunched together at the rear of the dash panel where it meets the gearbox tunnel. A difficult place to tighten the nut so just temporary sting a wire from there to the engine and see if that helps the instruments to work.
Tony

The ground Tony is describing is on the right side of the lower dash mount.

The main ground in the boot can be flakey. Longer term consider moving this ground to the right side body bolt threaded directly into the frame tower. This location is out of the road muck and as the bolt threads directly into the frame it gives better contact than the stock nut and bolt on the boot floor. That said, if the stock ground is clean and tight it should work OK to get going.

There is also a main ground up front associated with the steering rack mounting bolts. I removed this one as well as my Spyder sourced aftermarket loom provided heavy gauge ground wires to the front of the car. If fiddling with this, make sure you re-install any steering rack shims correctly as they are specific to each individual chassis.

Not really a main ground, but there is a short black wire that bridges the steering column universal joint so the horn button works. This can be deleted if an aftermarket solid metal universal is used.

How exactly the engine ground straps are positioned is lost to time in my car. As long as they bridge the engine mounts you should be good to go.

A ground strap runs from an engine mount to the coil mounting bracket for radio suppression. I find that to be a handy reliable ground point for troubleshooting under the bonnet. If it is missing the car should still run OK.

The Federal wiring diagram is a bit frustrating at first for sure as the layout is not a traditional schematic. That said, it is handy once you ‘get it’ as it sort of indicates the loom physical location. The good news is that it is actually very accurate; I cannot actually recall an error in the darned thing (once I figured it out! ). If not familiar with the British standard wire colours, for sure get a few charts that explain the colour system. Sounds like you are good to go from your Triumph experience. Lotus sorta followed the existing standard, although they kinda free lanced things like the window lifts as they probably weren’t covered when the car came out.

If you need help with a specific circuit in the Federal diagram there are several of us here that can help a lot as we feel your pain figuring out where each specific wire runs. Two circuits that are particularly quirky are the headlight and sidelight switching & relay setup (the Federal diagram is particularly confusing as the circuit was basically bodged when Fail Safe headlights were added) and the wiper circuit (as it uses some non standard colours in the Federal car). If the car won’t start make sure you have checked the immobilizer slide switch in the glove box. When posting questions in the electrical section make sure you clearly identify the car as a Federal Plus 2 though, as the other models are different in several areas.

All the best and welcome to the Federal Plus 2. It is a marvellous car!

HTH