1917 d45 carb questions

[Bob Engle]

I have been struggling to get my D45 running well.  I spent quite an amount of time on the electrical.  I kept losing my  distributor timing.  I found that the rotor was rubbing across the top of the pin the points are mounted to.  I added a .010" thicker brass washer under the distributor cam to raise the rotor.  I replaced the 7mm plug wires with 9mm wires.  The car still would not run with any power and the plugs are always sooty black.  The idle was very eratic and would stall frequently.  I ran a voltage check to the points and only had 5 volts while the battery was charged to 7 volts.  I found that the grounding from the battery to teh battery tray was severely corroded.  I removed the components and bead blasted them and coated the contact surfaces with dielectric grease.  Now I have 7 volts thoughout the electrical system.  Still runs poorly.

 

Today I  began to look at the  fuel system.  My vacuun fuel pump was gutted in the past and has an electric fuel pump with a return line back to the gas tank.  A gauge reading on the top of the tank shows 1/4 psi.  Running with the vaccum pump tank full and open to atmosphere still runs poorly.

I removed the carb today and have found some troubling areas.  The airvalve plate is loose in it's pivot pin.  Screws are tight, but the plate wiggles around.  There appears to be   a lot of play in the pivot pin.  I haven't removed the plate from the pivot pin because the plate ends below the pin are bend slightly to prevent the plate from being removed.  To bend the plate will put pressure on the pivot pin, possibly damging it.

 

So my questions are: 1.  Is the plate supposed to be loose?   2.  Are the  ends of the plate supposed to be bent?   3.  The plate has a hole in it, but in looking at the service manual cutway of the carb, it looks like there should be a tapered piece mounted to the plate to align the air valve spring on the plate.  Am i corret that this pice is missing?   4.  On reading info on these Marvel carbs, it is suggested to reduce the jet size to have the carb run better on 87 octane.  My current jet size is a #67 (.0320") drill bit size.  What is the recommended jet size?

 

Any help will be greatly appreciated

 

Bob Engle

 

[ROD W]

Bob, 

  The valve plate is not meant to be loose on the pivot pin.  It is meant to move freely  but not be loose.   You can see on this one,  at some time the pin has been replaced and the pin has been soldered onto the plate.   Are you missing the cone shaped spring locator on the air valve.  It looks like there is a hole in yours.  

Rod

[Bob Engle]

Thanks for your reply.  I am missing the cone piece, no wonder it didn't want to idle properly.  I will most likely have to ream the pivot pin bore and make an oversize piece to hold the plate properly.

 

Bob Engle

 

 

[Peter R.]

Bob,

I might have a good replacement plate including cone in stock.

Also, I have some early NOS Marvel assemblies in stock, which are soldered. It looks like they soldered the screws in the factory to prevent them from getting loose (on teens Marvels).

Peter

[DonMicheletti]

This is from my E-45. You can get an idea of the pin design. The pin locates the adjustment spring. Not having the pin is probably your problem.

[DGTryon]

From several carbs I have, the air valve (plate) is flat and rotates freely on the pin.  I do not believe the factory soldered the attachment screws but staked the back side typically.

The spring locating pin is critical as others have said.   I would be happy to discuss further your questions on electric pumps and adjustments.  My number is in the newsletters.

[Bob Engle]

I made the bullet nose piece and swaged onto the air valve today.  I debated about the air valve pivot pin and decided not to make a replacement today.  I don't have a reamer small enough to ream the hole true and make an oversize pin.  That's a winter project on the list.  The screws were soldered onto the pivot pin.  I filed the solder away and used a pair of vise grips to break the screws loose and turn them out.  I replaced the screws with SS 4-40 screws and let the threads run out the back side where I crimped the threads to keep the screws from working out.  I replaced the packing on the idle adjustment with  a nitrile O ring.  The packing had to be so tight to prevent leakage that it was difficult adjusting on a hot engine.  Teh O ring isn't leaking and it adjusts easily  now.

 

Carb is assembled and I poured gas in the bowl.  I've got a leak at the large nut on the bottom.  I'll tackle that in the morning  and fire it up and see  if I have made any progress on the lack of power/ running rich condition.  I can't see how I didn't improve the situation.  That hole in the air valve plate and a spring not kept in alignment had to be creating some problems.

 

I'd still like to hear about jet size changes and what works best.  

[DonMicheletti]

As far as I know, the jet in my '18 is original and it runs great. If I were you I'd be inclined to leave it alone, at least for now..

Also the shaft on my air valve is kind of sloppy too.

I had the same issue with the idle adjustment leak and ended up using a VITON  O ring. It hyas been in a couple of years now.

 

If you have copper seal washer on the bottom nut, you can anneal it by heating to red hot and quenching in water, that will soften the copper and probably seal OK on re-installation

 

[Peter R.]

21 hours ago, DGTryon said:

From several carbs I have, the air valve (plate) is flat and rotates freely on the pin.  I do not believe the factory soldered the attachment screws but staked the back side typically.

The spring locating pin is critical as others have said.   I would be happy to discuss further your questions on electric pumps and adjustments.  My number is in the newsletters.

 

I checked all my early Marvels and they are all soldered.

This assembly here has never been on a car and it is soldered too.

Does anyone know what it goes on to?

[Bob Engle]

Success today!!  I got the carb back in the car and made initial adjustments and checked for leaks.  The O ring on the idle meter works great.  I started the car and adjusted the idle meter for a smooth  idle.  The air valve needed to be adjusted for good throttle response. I took it out for a drive and it ran great.  Good power,  Speed was as fast as I want to drive it.  It did take a lot spark advance to get it to run good.  Almost to the end of the steering wheel adjustment.  Dean Tryon had told me that his car liked a lot of advance.  I parked the car and pulled a spark plug, good tan/light white color on the electrode,  first time I didn't find black soot.

 

I think I will go back and time the distributor  @ TDC rather than the book  7 degrees after TDC.  That should get me more lattitude on advance on the steering wheel.  

 

Thanks for everyone's assistance on the forum.  It sure makes this hobby a lot of fun to have a whole world of support to learn and solve the gremlins common to these early cars.

 

Bob Engle

 

[DonMicheletti]

With my engine timed at 7° ATDC, the spark is at approximately 1" BTDC (no mark) with the spark lever about the middle of the "RUNNING RANGE" on the quadrant.

There is a lot of linkage between the lever and distributor. You may have to take up slop in the pivots or the gear clearance at the bottom of the steering column.

Also be sure the centrifugal advance weights are free and not stuck.

 

Good to hear that you sorted out your carb problem.

[Hubert_25-25]

I would suggest that you look at eliminating linkage slop and that the mechanical weights in the distributor are working first.  You want to stay with 7 After TDC with the levers all the way up so that you still have the hand crank as a back up.  That sets a dangerous trap for anyone that tries to hand start the car if you don’t set it up per the book.   

[DonMicheletti]

If you try to hand crank it without a retarded spark, you'll never forget to retard it again.