|
|
|
My Euro-spec 1987 240GL has the B230K engine with a double-barreled Solex carburettor (1988 was the last year for carbs over here). 116 BHP, 10.5:1 compression, 192.2 Nm at 2.500 RPM. With the T-cam it pulls pretty strongly from the mark.
But recently the carb has been giving me headaches. It all started 5-6 weeks ago, when it didn't react to the manual choke. Not good, with winter approaching rapidly I knew I had to look into it "soon". Then the wife reported that the gas pedal was acting "funny" when she floored it. She had to step pretty hard to get it past a certain point. "Drive slower", I told her. Hmpf.
Last Wednesday I finally adjusted the choke cable until the valve had the prescribed 3.1 mm gap. But the engine did still not respond when applying choke. Hm. My wife took the car to work next morning, and I didn't get to drive it until Thursday night. When approaching a roundabout in town, I floored it to get ahead of a bus I otherwise would have had to stop for. The 116 wild horses came to life, the tranny kicked down, and "I won". But what the -! The throttle was jammed! In "full speed ahead" position! "Hmmm... interesting!" As I was less than a mile from home, I decided to take her home on the brakes. (Not knowing what was wrong, I did not know if I would be able to restart it if I stopped it.) Now this was a pretty exciting driving experience: The engine pulling like crazy, and my only controls were steering and brakes!
But as these were residential streets, the traffic came to a full stop when halfway home. All I could do was turn off the ignition and hit the warning lights. Just as well, it was only a matter of time before the brakes would overheat anyway. I opened the hood, and managed to pull the gas linkage free. The rest of the trip home was pretty uneventful until I was almost home, and I just had to check: Yup. Full throttle equals jammed throttle.
It was obvious that the choke linkage interfered with the throttle linkage. I assumed that the cause was my adjustments the night before, and redid it to the old position and thought this took care of the jammed throttle problem at least. My wife took the car to work next morning (scared and cautious), and everything seemed okay. "Well, it sounds a bit rough", she told me during dinner. In the evening I drove to the airport to pick up a visiting sister. I could see in the mirror that I was acting like a fog machine, and the engine did not sound good at all. It was obvious that the mixture was way too rich. I was not very surprised when the car refused to start when I had picked up my visitor. Seriously fouled plugs out, new ones in, and after a few tries it actually fired up. But it sounded as if the engine was running on three cylinders. We limped home, but on the driveway it finally died completely. I had to swallow all pride and ask my sister's help to push the useless heap of metal into the garage.
On Saturday I took "everything" apart, to get a real close look at this extremely complicated Solex Cisac carb. This is the last generation of carbs, and is brimming with vacuum lines in all colors you can possibly imagine, and electric wires are coming out of and going into it - only Mr. Solex in his heaven(?) knows what they do, my Volvo dealer surely doesn't.
However, a closer scrutiny revealed that in a particular position, the choke linkage would move about an inch sideways! The valve axle is simply a bolt, and this bolt had come loose. That was why the choke hadn't been working the last few weeks. That was why the choke linkage had been jamming its neighbour, the throttle linkage. And that was why the throttle linkage had eventually pushed on the choke linkage, resulting in full choke during normal driving.
A couple of turns with a 14 mm socket was all it took, once a correct diagnosis was established. With sandblasted sparkplugs it fired right up. A drive with high RPMs hopefully blew the combustion chambers clean. The engine is now purring like a happy cat, and the choke is again functional. Life is good. My brakes may be a bit worn though.
Thanks for listening,
Erling.
--
My 240 Page
|
|
-
|
|
|
KNowing what it looks like under the hood when things are working properly helps a lot when things go "south". I'm sure a naive mechanic would have billed you for a few hours to tighten up that 12mm nut.
A little frustrating but a simple cheap fix.
Good going Erling.
Oh, Watch your Mailbox. Your 'toys' should be showing up soon. So you can start another project.
--
'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me
|
|
-
|
|
|
Tony,
It really made my day when I found that loose bolt! I had all sorts of fears about what could be wrong, most of which I wouldn't have been capable of dealing with.
Got my hawk eyes fixed on the mailbox, you bet. Thanks!
Erling.
--
My 240 Page
|
|
-
|
|
|
Interesting story - glad it had a happy ending.
I am completely ignorant of those carbs. Wonder if you could post
a picture or two of them...
Many thanks
ps: according to what I have heard, blasting roughens the surface of the
insulator and makes it carbon up easier/faster, especially if the plugs
are not hot enough. (carbon won't stick to any surface hotter than 700°F)
|
|
-
|
|
|
George,
I just had a photo session... The Solex Cisac is a two-barrel, downdraught 34/34 mm carb. The ones used in the 240's had manual choke, the ones in the 740's had automatic and were (if possible) even more complicated. Add to their complexity that Volvo only used them for only a couple of years, and the result is that the dealer shops don't know them very well.
First, the engine bay, air box off:
A view down the barrels. Note: No removable chokes.
The two close neighbours, throttle and choke linkages. And bolt head:
Side view:
Regarding your advice against sandblasting, I certainly think it's a valid point. When I heard it, it was too late for these sets of plugs. Guess carb cleaner would have been better. I use a spot sandblaster with a rubber nozzle. Plug in, 1 sec. blast, and out comes a spotless plug.
Erling.
--
My 240 Page
|
|
-
|
|
I like to burn the carbon off, which the engine should be doing if it's running properly. Hit them with a Butane torch till they glow. A few minutes of that and they clean up nicely.
--
Drive it like you hate it
|
|
-
|
|
|
Great advice, I'll try that, thanks! The reason I have been sandblasting is that when I was a kid, every auto shop had a sandblasting unit for sparkplug cleaning, and the spot sandblaster I already had seemed like an ideal tool for the job. But it will inevitably result in a rougher surface, which is obviously not good.
Erling.
--
My 240 Page
|
|
-
|
|
|
"Seriously fouled plugs out, new ones in, and after a few tries it actually fired up. "
What would lead you to carry a set of spare plugs (and approriate tools) with you. Are fouled plugs common (as plugs aren't likely to suddenly die)?
--
1980 245 Canadian B21A with SU carb and M46 trans
|
|
-
|
|
|
Hard earned experience.
My car is mostly used for shorter trips, and the carb'ed cars I have had (this one included), has had a tendency towards fouling that my single EFI car never had. I guess that if the engine got a chance to get thorougly heated up each time, the problem would have been less pronounced. I use one grade hoter plugs than normal, which reduced the problem. So I'm used to removing the plugs every now and then to sandblast them as a preventive maintenance. I keep an extra set and a tool in the boot just in case, sometimes I get sloppy in caring for my plugs.
Before you ask, the carb was professionally rebuilt two and a half years / 25,000 km ago, so I assume there is little to gain adjustment-wise. I had the CO optimized for 2,000 RPM. Of course, there's always the MAP-sensor.
Erling.
--
My 240 Page
|
|
|
|
|
