• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Wouldn't Start, Now Starts but Revs to 6000+

Share this page

theleisure

theleisure

Jedi Trainee
Bronze
Country flag
Offline
Hi guys,

My car has a '66 1098 with a 40DCOE. I installed a new in-line plastic/paper fuel filter about a month ago.

Was running great until Tuesday. Went out to the car on Tuesday and it wouldn't start. Tried jumping it but still nothing. It's been cold and snowy here lately so I gave up trying until today. I replaced the battery and plugs and tried again. Still wouldn't fire. It's cranking really well, seems to be getting gas and the plugs fire when removed and touched to block. I sprayed a little bit of starting fluid in and it fired up right away-- like immediately. Now when I start it it starts right up but goes to 6000+ rpms right away and doesn't come down. Don't want to let it do that cold. Heck, wouldn't want it to rev that way warm. dang.

Is there something stuck in the carb that's causing too much fuel to get in? When I sprayed in the starting fluid I only sprayed for about a second into each carb throat so I don't think that would be the problem for more than a moment.

One other item that may or may not be an issue is that I filled my gas tank on Monday morning from close to empty. When I turned the car on after filling up, the gauge read 1/4 tank even though it was full. When I turned the car off it went back to E and then back up to 1/4 when I turned the car on again. On Tuesday I went out to the car and the gauge read accurately but the car wouldn't start. I assume the problems are unrelated but maybe they point to some other problem.


Looking forward to reading your input.

Thanks,

Sean
 

Attachments

  • 20216.jpg
    20216.jpg
    61.1 KB · Views: 381
It is usually the last thing you did when these things happen. So I would guess water in the fuel. If is not a lot, like a 1/4 tank, I would add some Heet, the isopropanol kind not the methanol kind. Then go inside and watch the Olympics for 15 minutes or so. Isopropanol melts ice and will work its way through the fuel system. I have used with diesel with great success. Just be sure it is not methanol. Methanol will not melt ice so you would have to watch the Olympics until the spring thaw for it to work.
 
Carb stuck at WOT?
Think "Toyota" :wink:
 
I'm just guessing here as I'm not familiar with the 40DCOE but could you have a stuck float that is flooding the engine? Then when the starting fluid was sprayed in, that was enough to get it started and sucking all that raw fuel in, thus revving it to 6K? Just a guess.

Good luck!

JACK
 
I went back out to try it again about 20 minutes ago and it's back in "not going to start" mode. I guess the revs were from the starting fluid. I went and bought some Iso-Heet and added a half bottle to the tank. A full bottle treats 20 gallons so 1/2 bottle should be more than enough.

I'll let that heet stuff sit in there for a while and try again around 4ish. It's finally above freezing outside today-- 37 degrees. I doubt that it'll go down below freezing before then...
 
Its got to be a butterfly valve stuck open. It don't matter how much fuel, it ain't going to rev without air and the butterfly controls the air. Either something in one or both butterflys or they are stuck in position from the cold or the linkage has gone all Toyota on you :wink:
 
or a stuck float valve. Stuck closed.
 
To "unstuck" a float valve on a DCOE is th' same proceedure as an SU... pump on, and with the handle of a screwdriver pick a flat spot on the left side of the top of the carb and give it a few smart whacks.

The full throttle response thing wouldn't happen if the return spring is proper.
 
DrEntropy said:
The full throttle response thing wouldn't happen if the return spring is proper.
Click to expand...

I can definitely figure out how to whack the top of the carb with a handle but whatd'ya mean about the full throttle response thing and the spring? From the outside it appears as if the spring pulls the linkage closed. Is that the spring you're referring to or do you mean the one on the inside?

Luckily some idiot skier broke the mirror off of the driver side wing of my car while skiing down my street recently. I can use that mirror to look into my carb to observe the throttle valves tomorrow.
 
The DCOE's can actually overcome a throttle return spring if it doesn't have enuff tension. The beast will go to WOT in an eyeblink. If your spring is strong enuff to slam the throttle closed after a rev or two then that's not the problem. I mention'd it only as a circumstance I've seen more than once, a cautionary bit of info.
 
theleisure said:
WOT? Sorry, not sure what that one means. The throttle moves freely and returns to the stop at the carb.
Click to expand...

and no one answered your question WOT means wide open throttle. (I didn't know first time either)
 
Went out to the car and used the mirror that the skier broke off to confirm that the butterflies (throttle valves) are behaving as they should. Now I'm sitting inside drinking coffee and letting some time pass before I risk waking the neighbors with what may or may not still be 6000+ rpm of unbaffled 1098 exhaust noise.

here's a general parts diagram for a dcoe. Out of curiosity, which part would be the stuck float valve?
 
#8.

It will only be evident the spring is weak when the thing is running. With no air moving thru, the spring will work fine.
 
Aside: I saw what appears to be the "States steets" in th' background...

Does: "Brother Dan & Sister Ann" ring any bells? :wink:

Another thing to be aware of with DCOE's is the choke lever. If it doesn't have a cable attached, be SURE it's held home (closed), as the choke pistons can allow fuel past if not well seated. It can cause a LOT of head scratching when setting (or attempting to set) idle.
 
That choke comment has me thinking now. Maybe I left the choke pulled out after the car wouldn't start on tuesday. I guess, with the car parked facing downhill, that that could have allowed fuel to flow. Maybe?

The background features some of the lovely views offered in Lawrenceville...

I don't really know much about Brother Dan & Sister Ann other than it was some scandal that my mom and dad would talk about. I associate the memory of those stories with a church out on Mcknight Road in the N. Hills that we would pass on the way into town before they built 279 North. Not sure if they were actually affiliated with that church or not. I also think of them in connection to some Baskin Robbins/ mob scandal. None of it makes much sense to me, they're 25-30 year old memories I bet.
 
Back
Top