lag over 3K RPM

[1967stang302]

OK, so first I have to get this out of the way, I moved in JAn and finally just shipped my car over to my new country of residence. been 9 mnths to the day since the car was driven, got it off the boat with the last of my cash, so no abuse on what I did next. I changed the oil right before I moved, and I know 3 months or 30K. well, been festering for 9 months and only driven 110 miles since then, but I drove it off the boat and 488Kilometers home, too tired to convert... I drove 5 minutes and when I drive I get this lag, I get the car revved up to 2500RPM and it feels like the gas is cutting out. I drive a while because I have to get home since I cannot afford to tow or get the work done there... I drive the distance and through hours of driving the lag moves to 3KRPM. It's still being a pain and I am tomorrow morning taking it in for a FULL service, but seeing as how an oil change here costs $140 at an average place, I want to get some ideas on where the issue may be. I have many ideas and can answer any questions, but this is a new engine 10K miles and a new tranny 3K miles. 302 and T5 with, well you can read my signature... any ideas folks, and I know the obvious flaws in my plans, andby the way, when I rev the engine past 3K I cannot notice any discernable issues with the lag. It just feels like someone snuck on a governor on my carb which I know is not remotely possible...

 

[dennis112]

OK, so first I have to get this out of the way, I moved in JAn and finally just shipped my car over to my new country of residence. been 9 mnths to the day since the car was driven, got it off the boat with the last of my cash, so no abuse on what I did next. I changed the oil right before I moved, and I know 3 months or 30K. well, been festering for 9 months and only driven 110 miles since then, but I drove it off the boat and 488Kilometers home, too tired to convert... I drove 5 minutes and when I drive I get this lag, I get the car revved up to 2500RPM and it feels like the gas is cutting out. I drive a while because I have to get home since I cannot afford to tow or get the work done there... I drive the distance and through hours of driving the lag moves to 3KRPM. It's still being a pain and I am tomorrow morning taking it in for a FULL service, but seeing as how an oil change here costs $140 at an average place, I want to get some ideas on where the issue may be. I have many ideas and can answer any questions, but this is a new engine 10K miles and a new tranny 3K miles. 302 and T5 with, well you can read my signature... any ideas folks, and I know the obvious flaws in my plans, andby the way, when I rev the engine past 3K I cannot notice any discernable issues with the lag. It just feels like someone snuck on a governor on my carb which I know is not remotely possible...

I used to live in Italy and had seen many cars arrive that wouldn't idle or cruise as well (and sometimes not at all) as when they were put on the boat. Most often the cause was dried up fuel in the carburator. The little internal passages would plug up in as little as 2 months from the last time the cars were driven. We normally boiled it out and chased the passages to clean them out.

You may also want to have the fuel filter replaced.

 

[2nd Mustang]

Any changes in altitude? I know carbed engines really change drastically due to altitude. I even noticed the change in my 2003 Toyota pickup when I spent a week in the mountains. It was oh so slight, but noticeable.

 

[1967stang302]

I used to live in Italy and had seen many cars arrive that wouldn't idle or cruise as well (and sometimes not at all) as when they were put on the boat. Most often the cause was dried up fuel in the carburator. The little internal passages would plug up in as little as 2 months from the last time the cars were driven. We normally boiled it out and chased the passages to clean them out.

You may also want to have the fuel filter replaced.

I figured it was a clogged fuel line or something of the sort, so I think I will try what you have said, the only thing is when I rev the engine in neutral, it sounds almost perfect, it is only when I put stress on the engine, I was afraid the header gaskets may have dried out and I got a small hole in one. As for boiling out and chasing the carb, know where I can find instructions online so I don't destroy it?

 

[SoCalCruising]

I'm with dennis 112. Get the carb serviced. My 650DP likes to be driven weekly. If I leave it for two weeks, it often won't idle well (or at all) until its been run for 15-20 mins.

 

[dennis112]

As for boiling out and chasing the carb, know where I can find instructions online so I don't destroy it?

I can't direct you to any specific site, but can give you some pointers.

First, what type of carb do you have? Is it a stock ford 2bbl, holley, or edelbrock?

Since your car actually runs, you might want to dump some fuel injection/carb cleaner into the tank. Many of the cars we worked on needed pushed around because they just wouldn't run at all, or wouldn't idle.

More specifically on cleaning a carb when overseas:

You will probably need a rebuild kit for your specific carb so I recommend getting one before any disassembly. Common carburator cleaner may or may not work for soaking. I couldn't find it in Italy and so made do with lacquer thinner or kerosene.

No matter what you use to soak the carb in, it is imperative that you have access to compressed air to blow out all the internal passages.

Anyways we did some really bizarre things to clean up the really nasty carbs. Dried gas can be really tough to remove from passages. We found that soaking the carb in toilet bowl cleaner (possibly the Tidy Bowl brand) did a great job of loosening up dried deposits. Unfortunately it also removed the factory plating found on carbs so if maintaining factor appearance is important, you will not want to soak it for long. It did work well though.

In severe cases, I got some stuff from a photo lab that would literally eat away at the carb. The stuff actually bubbled profusely when the carb was put into it so soaking had to be limited to 30-40 seconds. Chasing carb ports was also under the extremes and is not really recommended for a beginner. Basically we removed the factory plugs and ran small wires up each passage to ensure they were clear. Once satisfied we installed lead plugs or used JB weld to plug the passage. It must be noted that the cars we worked on were people's daily drivers and they didn't care what was done as long as they could drive there car. On a classic, these methods certainly wouldn't be high on my list of things to do.

If you are unsure of your abilities, seek the help of a professional.

And be sure to check that fuel filter before doing anything else.