1933 V8: Troubleshooting...suggestions welcome

[torpedo]

Dear Barners,


Most of the time I try to figure out by myself when I face problems but on this one...


Some background: stock 1933 221ci - 6V positive ground - Stromberg 97 - stock dizzy (supplied by ThirdGen - less than 1000 miles on it).

https://www.transferxl.com/download/08vzcSq5t3KcNC


If you can't access the video on link above, the symptoms are that engine power is not coming when going full throttle. Above certain RPM it roars but without delivering power, just as if there was a limiter...



Troubleshooting done so far:
1. Replaced fuel filter > problem still there
2. Carburetor inspected, cleaned, checked power jet OK

At this stage the fuel supply issue was eliminated.


3. Played with dizzy adjustments like vacuum advance nut or ignition timing. This was probably a mistake because a. ThirdGen supplies them "ready and good to go" b. it's been working before without a miss c. I do not have the machine to setup dizzy.
4. Decided to swap dizzy with an identical unit (backup) also supplied by Michael. Problem still there.
5. I have good spark at coil

Thanks in advance for your suggestions/opinions

[Terry,OH]

How is the clutch. The 97 accelerator linkage rod should be about 3.75" long. Make sure the adjustment for the power valve is correct, there may be a "Stromberg How To". When the foot pedal is depressed fully the Carb. throttle opens fully. The air cleaner is not restricting air flow, try removing it.

[Ggmac]

Blocked exhaust ? What is the vacuum gauge saying ?

[torpedo]

Hi Terry,
Clutch was renewed 23/10. Has been operating satisfactorily since.
Stromberg carburetor was entirely checked and operates OK. Tried removing air filter. DOes not solve issue.
Thanks for your suggestions.

[torpedo]

Hi Ggmac,
Exhaust was replaced with new 22/07. What additional test should I perform on it ?
Unfortunately I do not have a vacuum gauge...
Thanks for your suggestions.

[kurt v]

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don't know about a 97 but my 94 was not running right, took time to work it out it out, one of the two barrels of the carb was some what plugged up car ran and started but just was not right. Cleaned carb real good ran great, don't know where junk came from but it must have been the only piece .
kurt

[dean333]

Send the carb and fuel pump to Charlie Schwendler for thorough cleaning and upgrades to gaskets that are compatible to the lousy fuel.

[torpedo]

Hi Kurt and Tim,
Thanks for the tips. I value your points.
As stated earlier, carb was entirely cleaned and checked by a professional and deemed to be functional. No gasket leaks either...

[kurt v]

that doesn't mean that it hasn't picked up a small piece of junk after carb was installed

[Ggmac]

Vacuum gauges are cheap , suggested you by or borrow one . It’ll tell you what’s happening by the needle, either steady and dropping or bouncing ( another issue)
Any weezing sounds along the exhaust route or enough exhaust coming out the tail pipe ?
Have you hit anything or had it up on a lift . Mounting on a lift with some one not knowing how to set it up can do damage to tank or exhaust.

[Flathead Fever]

Make sure the linkage to the carb is adjusted so it's opening up all the way at wide open throttle.

[jimTN]

Are you saying the engine will not pro0duce full RPM? If it runs smooth up to a point and will not go further, its going to be a minor problem. If that is the case, remove the throttle rod and manually open the throttle to see if you get more rpm. Did you get full rpm before these changes?

[torpedo]

Hi Jim & other contributors,
Engine will not produce full RPM. On the road in 3rd gear it will not go beyond 45 mph. A month ago I could reach 65. This issue has not surfaced overnight though.
Carburetor operation was checked and cleaned thoroughly. Air filter removed, rods disconnected...
The link provided above allows download of a file in zip container. Open container and you'll find a short video that illustrates the issue...
No suspicious sounds from the exhaust. Car not lifted before the issue arose.
I'll try to find a vacuum gauge in the meantime.
Thanks guys for your help.

[kurt v]

Are you using older fuel lines with the new gas ?

[petehoovie]

Like kurt v said above, I too suspect the carburetor (even though it has been gone through by a pro). The symptoms you describe and the video, it sounds like it's running on just four cylinders. I had a Stromberg 97 in my '37 that did what you are experiencing...

[torpedo]

Thanks for more suggestions. Tomorrow we will perform test to bypass tank & fuel pump and recheck carb.

[Fairlane514]

Check timing and firing order. I cant see the video, but based on what petehoovie said, if it is only running on four cylinders.....

[deuce lover]

Put a vacuum gauge on that engine.It will give you a good idea what is wrong.

[TJ]

Kurt v asked a good question. Have you changed the flex line to the fuel pump? If it's an old line it may have cracks in it or the line inside may be coming loose.

[torpedo]

Hi Gentlemen,
Thanks for your contributions. It really helps to progress.
As far as fuel line and associated components are concerned, all were checked/renewed as necessary in 2021: lines from tank, fuel pump restored to original (with components from Joe's Antique), carburetor opened (parts checked and cleaned) and tested OK. Later today I will make a test to bypass fuel pump...