Question regarding use of thinner for carburetor powered engines..

M

mitch08

New member
Hi guys. Sorry I couldn't find any thread that would fit in for this.. I just had my Mitsubishi Lancer 1992 EL carburetor cleaned today. Everything seems well, except for this: I noticed that the repair guy directly poured thinner on the carburetor while running my engine before a test drive. Before I went to their shop, my main complaint is that the engine really takes time to start and it suddenly stops while driving. At one point I had to pour gasoline directly to the carb so it would run. However this time around, the guy used thinner. I know he used it to clean the actual carb but is it recommended to pour it directly into the carb while the engine is on?? One thing I noticed too is that at one point today my car suddenly stopped again. I needed to push on the accelerator further to have it run smoothly again, though this happened only twice. Aside from those 2 instances, everything seems to be smoothly going. So that sums up to my main question, is it safe to pour thinner directly to the carb while engine is running? If not, what should I do? Should I have an engine oil change already and drain the gasoline? Thanks in advance..
 
Are you speaking about paint/lacquer thinner?

If so, it shouldn't hurt anything as long as it's not constantly ran through the engine. Believe it or not the ingredients are very similar to a lot of the cleaners that you can buy at the local parts store.

I wouldn't fret it but I also wouldn't do it again.
 
I don't think he was actually pouring the thinner into the carb was he? he may have used it to check for air leaks around the carb, intake, etc, as it causes changes in idle speed when a leak is present. I would definitely be adding a fuel system cleaner to your gas tank regularly as a preventative. the alcohol can gel after awhile an wreak havoc on the fuel system. make sure the air filter is clean and maybe change your pcv valve too. they do make carb cleaner spray, just be careful not to get any on painted surfaces, the results can be ugly.
 
Check your fuel pump as well. Today's higher ethanol/gasoline blends required by law these days plays havoc on the seals of any pre-1995 car that may not be Original Equipment of Manufacturer (OEM)engineered and built with ethanol (grain alcohol)-compatible seals.

Car collector and TV night show comedian Jay Leno wrote an article in AutoWeek Magazine recently about this very problem and how much damage ethanol is doing in older car's fuel systems (carbs,gas tanks, fuel pumps, fuel filters). it's a very real and expensive "problem" within his collection of older cars, especially since he runs his rare and museum-quality cars for special events (car shows, rallies, or just for fun for guests car enthusiast/collectors). His contention is that we (car enthusiast) should lobby Congress to repeal the ethanol requirement in gas law.
 
Hey guys! Thanks for the feedback.. Yes, it is a paint/lacquer thinner. I saw it when he poured it directly to the carb, right where I use to pour gasoline when the car won't start after a week of not being able to start the engine. So I guess my follow up question is should I change the oil given that the thinner is already on the engine?? I already had 10kms on it since it the carb was cleaned.. Also, aside from oil change (if needed), what are the other things that I should do?? I mean should I totally drain the gasoline in the tank and replace it with a new one?? Thanks in advance..
 
I would just continue with normal maintenance. I you're due for an oil change get one. It shouldn't have gotten much into the oil. It's an old trick to clean out your fuel system.

Of it gives you peace of mind to have it changed though, go get an oil change. You really can't go wrong getting your oil changed before the interval.
 
I'm an old carburetor guy and because of that I have to ask - were you just getting it cleaned, or were you getting it rebuilt and of course, it would be cleaned at the same time ???
If it stops working and you have to give it more gas, you have other issues that are not going to be solved by just cleaning, Im afraid..

I would be checking really close for any vacuum leaks and replacing any hoses that are looking less than new with cracks, drying, etc.
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Then, I would be looking at the carb to see if I can determine the float level and if the accelerator pump in the carb is really working correctly.. Usually this rubber/viton, etc., part wears out and then when you need it to give you gas it gives you less and less..

Any carb needs to be periodically removed, taken apart, soaked in a good carb cleaner, then have air blown through all the passages to insure they are clear, especially all the jets,.., etc...

All the gaskets that hold it all together do go bad and shrink and this can also lead to issues..

The mounting gasket/s need to be changed out to insure its still flat and sealing the carb to the intake manifold...

Squirting any carb cleaner into the carb opening while its running is pretty much the same as putting what this guy put in there, but why he poured it in is beyond me.. I just thought of something - he might have been trying to clean the throttle body shafts as they can sometimes get a coating of gunk and then they wont open properly.. :)

I believe some of these fluids will get into the engine oil but how much is bad for your particular case is really hard to say over the internet without seeing it happen..

Fortunately, your oil and filter are great at what they do, and just so you know what I do, If I ever run a bottle of gas tank fuel injector into the tank and run that tank of gas through, I will always plan to do this right about when I get the oil changed afterwards.. :)

Good luck with your project !
Dan F
 
Water poured down the venturis would do little to clean the carb. maybe a bit on the throttle plates or shafts. From the description of the service I almost wonder if he was performing a service of which you weren't aware. Back in the day it wasn't at all uncommon to clean carbon from the engine using either the PCV port or by pooring the cleaner directly into the carb. The PCV port made for a much smoother operation during this procedure.

Surprising as it may be water mixed with solvents introduced at a slow rate will do a number on carbon on the valves and tops of pistons. I've seen many variations of this, sometimes water mixed with automatic transmission fluid, acetone, diesel fuel and water and various solvents

The commercial grade cleaners were no doubt some combination of solvents. This usually made the engine smoke severly and the engine wanted to stall while it was being performed. Of course that meant opening the throttle plates and reving the engine. Most of the commercial products would have you put this in the engine and once the can was empty let the engine sit for 30 minutes or so for the solvents to do their thing in a hot engine. I've litterallty seen deposits blown from the tail pipe (meaning solids) following this procedure.

The down side was that this usually did a number on the plugs so this service was almost always performed before the actual tune up. I also saw in one instance where it knocked the carbon loose and trapped it between the exhaust valve and seat losing compression in that cylinder. Even after much attention including repeating the process the head of a 2.3 liter Ford ended up being pulled. The carbon was sitting on the valve face as big as life and literally needed to be knocked off. It was the mechanics Mustang II, the guides were nasty and it ended up leading to a valve job. Anyway...
 
Hey guys. Thanks again for the feedback! Really appreciate it. I guess I would just have the oil changed just for my peace of mind. He-he.. I'm not really savvy in terms of cars so I'm not so sure as well if he was already doing a rebuild or just cleaning. Just to describe what he did, he removed the carb from the car, disassembled it, soaked it in thinner, used a blower like thing to clean the carb, replaced fuel filter, removed the spark plug to check it, and then placed back the carb. Then poured the damn lacquer in the carb to make the engine run since he disposed the remaining fuel on the old fuel filter. Ha-ha-ha. But as I've said, it worked kinda fine, except that it stalled 2x roughly around the 6-7km mark after the carb cleaning. Right now odometer is at 10kms.

And also one more thing... Do you think the lacquer got mixed up with the remaining gasoline in my tank? Or it just went directly to the engine? Sorry.. I'm not really a car genius..
 
No it won't end up in your tank. He probably didn't hurt anything. It kind of sounds like he just primed it to get the pump pushing gas. Pull your dipstick and smell the oil. If it smells like solvent or it's been a while change it.
 
I am glad it works hopefully better for you and hope it doesnt decide to stall when you just merged into a California freeway where the slow lane is doing 80mph...

Something else - did I miss this - did he change the fuel filter out if the carb has one either in the gas line entrance or around that area in the gas line ??
These guys can mess around with your performance at times, and should be changed regularly..

At some point, if it has not been done in who knows how long, that carb needs to be rebuilt with a new gasket set, accelerator pump piston, new float, needle and seat, and all the other parts that wear or erode, changed, then installed and adjusted to work right again.
A few places, like the float assembly need to be at a certain height and have a certain float drop measurement, and then it has to be checked to insure it is right for this application..

Good luck with this..
Dan F
 
Dan, I agree completely with the carb rebuild. That said, Mitsubishi carbs and Thermoquads were always my least favorite carbs to rebuild. For markedly different reasons but the those two always made my nose wrinkle.
 
Yup, I think that's the right term.. He "primed" it just to make the engine run.. Like IV lines huh. Heheh.. And yes, he did changed the fuel filter.. though I'm not exactly sure with the gas line entrance thing because again, I'm not car savvy. Ha-ha.. But from what I noticed, the fuel filter is almost beside the compressor? (if I got the right term for that motor like thing).. so yeah. He-he. I'll give it a shot first: I'll smell the oil first before doing an oil change! :D
 
Hi guys. I finally had an oil changed. Spark plugs were also changed and I found out they are dark at the tip. However, the problem still persist, or probably, worsened. After using the vehicle yesterday, it is very hard to start as of this morning. It feels like it hasn't been used for a month or so. I don't think it's a problem with the starter because there is some sort of kick in it when I try to start it. The problem is it won't start not unless I pump the accelerator. After it starts, it would like choke up a bit and it would run really rough on idle. If I depress the accelerator, it would choke again and the engine would turn off. I brought it to the b.s mechanic who repaired it and he told me that it is normal for carburetor powered engine to prime gasoline so it would run smooth. I believe otherwise. Because before I brought it to him, it was working much better except it eats up a lot of fuel. Now it doesn't seem to consume a lot of gas but during cold starts it's really a drag. Any ideas on this? Could it be a problem with air fuel mixture? Could it be the fuel pump or distributor? And what are the ways to check for such so I can instruct that S.O.B to do so when I come back this week on their shop? Thanks in advance..
 
Choke adjustment. As you didn't mention black smoke or rich smell it might be adjusted lean. My experience is however that many adjust the choke too tight especially as you get an engine that has a few miles on it. Sounds like it's time for you to make the switch to a fuel injected vehicle. Carbs can be temperamental but typically once one learns their habits aren't something you can't work with.
 
Thanks for the reply @GearHead_1 :D I don't think I saw a black smoke on the tail pipe, neither do I smell anything like fuel (I don't know exactly what you mean when you said rich smell sorry)..
 
mitch08 said:
Thanks for the reply @GearHead_1 :D I don't think I saw a black smoke on the tail pipe, neither do I smell anything like fuel (I don't know exactly what you mean when you said rich smell sorry)..
Click to expand...

It pretty much means that your exhaust smells like fuel that didn't get burned... Which smells pretty much like fuel.
 
GearHead_1 said:
Choke adjustment. As you didn't mention black smoke or rich smell it might be adjusted lean. My experience is however that many adjust the choke too tight especially as you get an engine that has a few miles on it. Sounds like it's time for you to make the switch to a fuel injected vehicle. Carbs can be temperamental but typically once one learns their habits aren't something you can't work with.
Click to expand...

I like carbs. Both to eat and on cars......... !!

At least I could work on carburetors
 
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