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EFV-8 Club Forum / General Ford Discussion / RPM slows down

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Posted By Discussion Topic: RPM slows down -- page: 1 2     Kens 36 03-09-2024 @ 8:36 AM reply profile send p.m. Member Posts: 343 Joined: Oct 2009 Mr. Gasket air filter v. stock. It's your car, do what you want. But sorry, personal preference. I'll stick with the stock oil-bath air cleaner that has served my car well for 74 years. Stock air cleaners should be readily available for a 1946 Ford. Ken same 03-09-2024 @ 6:53 AM reply profile send p.m. Member Posts: 92 Joined: Jun 2020 46coupe,if your still interested in an after market air cleaner iv'e also found those little 2" tripower air cleaners are too restictive . iv'e since went with a Mr.Gasket part#1490 6 1/2"which is actually 6 7/8" kit comes with paper element, metal base that fits over the holly ford 94 carb,and a chrome cover,and wing nut. has worked much better.had this filter kit on the dennis carpenter replacement 94 for two years now. Tom. 46coupe 03-08-2024 @ 4:34 AM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 i finally got to test drive the car. I installed a new air filter which isn't exactly the same as the other one. The car drove very well. Like someone suggested it looks like the engine was starving for air. Thanks to everyone for your help and suggestions. Have a great weekend and drive those V8s 46coupe 02-22-2024 @ 10:31 AM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 Thank you for the site info. I'll check there. My paper filter is 2X8 which will fit inside the original air cleaner. 46coupe 02-22-2024 @ 10:12 AM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 Thanks for the additional items to check. Ill try the MM drizzle in the carb. I'll have to check my notes on the spark plugs or pull one out. Compression has been good. The distributor was new or rebuilt before I bought the car. I will, however, check the vacuum advance. The other items from previous posts will be addressed also. Drbrown 02-22-2024 @ 8:26 AM reply profile send p.m. Senior Posts: 570 Joined: Nov 2013 Your description of how it runs rough at startup interests me. If your choke is adjusted well the engine should smooth out after only a half to one minute. Obviously temperature effects this. You say you need to run at elevated RPM for about five minutes and to me that seems normal. OTHERWISE THOUGHTS: (1) Some folks use a slightly hotter spark plug and they warm up faster i.e. my '47 came with Champion H-11's instead of stock H-10's ..... why I don't know as it doesn't burn oil but none the less it runs well with either of them. (2) A leaky/sticky valve can show in three ways: hold you hand over the exhaust pipe to feel for any irregularity in the gases coming out; better yet put a vacuum gage on the engine - a sticky valve will make the gauge needle bounce, and/or do compression checks as a leaky valve [or other defect] may show with that. Some MM Oil drizzled down the carb and in your motor oil helps alleviate a sticky valve. (3) Excepting a bad coil, air temperature should not effect operation of the ignition system. That it runs smooth when warmed-up and running is a good under load is a sign that the carb, distributor, plugs and plug wiring are functioning well. In the end, if you are still experiencing RPM drop under conditions you state then I still think its a problem with gas supply. Although your descriptions indicate otherwise, there's a remote outside chance that under load, with the related drop in vacuum, that your distributor advance is not working well. This message was edited by Drbrown on 2-22-24 @ 8:31 AM carcrazy 02-21-2024 @ 9:45 PM reply profile send p.m. Senior Posts: 1659 Joined: Oct 2009 I agree with you, I don't want to run one of those tiny chrome things on my Flathead Ford. If you have room for a 10" diameter air cleaner, you can run an air cleaner from Speedway. It is P.N. 240-1195 and uses a 10" dia. X 2" tall air filter (P.N. 91011098). To use this air cleaner on your Ford/Holley 2V carburetor, you will also have to purchase a 4" dia. air cleaner, P.N. 91011005 for parts. The parts to use from this 4" dia. unit are the mounting bracket that accepts the mounting stud and wingnut and the hose clamp to mount the bracket to your carburetor airhorn. carcrazy 02-21-2024 @ 4:47 PM reply profile send p.m. Senior Posts: 1659 Joined: Oct 2009 Measure the dimensions of your paper air filter and search the air filter elements available from Speedway Motors. Their website is speedwaymotors.com. If they don't have the size you require, you can bring your old air filter to a local NAPA or other auto parts store to see if they either have one in stock or can order the proper size filter for you. 46coupe 02-21-2024 @ 2:03 PM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 I finally got some time to run some experiments. Checked the gas cap and it's ok. I had taken the air cleaner off and sprayed carb cleaner in it. On start up the engine ran rough but after about 5 minutes it cleared up and kept running without skipping or slowing down. T he the carb cleaner was used then. Well I took it on a test drive of 15 miles and it ran great. I had to stop for lights and general traffic and had no problem. I hope this has fixed the problem. However, I' m going to keep checking the other things you all mentioned. One thing that I was going to ask, and my question was answered when someone suggested removing the air cleaner. I have the stock air cleaner but the guts of it have been removed and a regular paper air filter was installed. I have searched several places to find a replacement using the dimensions of the air filter but have not been successful. Not wanting to introduce dirt and debris into the carb, I turned the filter upside down to expose the new part of it to the air. Could this be what has caused the problem? Would anyone know what air filter might fit? I am trying hard not to have to use one of those tiny chrome things. Does anyone sell the inside "cartridge" for an oil bath air cleaner? 46coupe 02-20-2024 @ 1:29 PM reply profile send p.m. Member Posts: 271 Joined: Oct 2015 Thanks for all the suggestions. I hope to have time tomorrow to do some troubleshooting. I know the tank is full. I am using 4oz of MM in the gas tank. I have the original fuel setup, no electric pump. When I first start the car after it sits for a couple of weeks, it runs very rough and dies if I don't keep it at about 1200-1500 rpms. After running a few minutes it smooths out. I wondered if I have a sticking valve . The coil is new. The old one would fail to restart the car when it was hot. I kept it and might try it if the problem continues. Before that I will try the carb cleaner and check the float level and fuel volume. The tank is vented, so much so that I have to seal the cap to keep the gas from evaporating. I'll get back to you all to let you know what I've found.

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