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I have a G200 with electronic ignition. It started stumbling on the freeway and now stumbles going up hill. I have timing at 12 degrees. On my last truck, replacing the pick up fixed this issue. I have the old distributor, module, and pick up from my last truck so I swapped the magnetic pick up. Still not doing any better. Should I check something else or keep adjusting the gap? Should I set the timing at 3000 rpm with a digital light?

It has fresh gas but it's ARCO gas.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Check our fuel filters.Also check the volume of fuel coming out of your fuel pump.Check your plugs.Make sure you don't have any vacuum leaks.

just puttin this in the ring too, with arco gas try to avoid getting gas when they have a tanker refilling the tanks, seems to stir up the crap in the bottom of their tanks, my girlriends acura runs and sputters worse if she gets gas during

the timing info is under the hood unless yours is missing im assuming the g200 and g180 are very close for timing specs

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Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

So I readjusted the mix and idle on carb. I set the magnetic pick up to a very close gap, re-timed the motor to 12. 6 was causing the studdering and it had no power. I think it's better at 12.

I'm thinking I will check the fuel filter when I get a chance. I don't think it is this though, doesn't feel like fuel pressure issue. When I give it gas, it doesnt make it worse.

Vacuum leak sounds interesting, like if the vacuum advance wasnt working at some rpms. The motor doesnt start stumbling until 2700.

I could start replacing coil, rotor, and the ignition module, but all these parts are new. Last time I had this issue (on a different truck) I went through and replaced all that stuff but it was the magnetic pickup that caused the problem.

As I said, I have swapped that for another one I had laying around, that I know to be good, and it didnt help. I have tried various gaps and that doesn't help. Further seems to make it worse. Perhaps I will try making it as close as f-ing possible.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

pretty sure i gapped mine with a match box cover

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Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

Checked fuel filter. Poured fuel back through it the wrong way and no dirt came out.

Sprayed carb cleaner around all vacuum points and hoses and got no idle increase. I put some zip ties around some hoses I thought could be loose at higher rpm.

I checked the vacuum advance by speeding up the motor and pulling the vacuum line off and plugging it. Vacuum advance is def working, even at idle. Perhaps I should reset the idle timing with distributor unplugged.

Too much traffic to really test out if it worked or not.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Did you set your timing with the vacuum advance plugged? That would cause an issue.Also check your air filter..if it can't get air under load it will stumble.Check to make sure accelerator pump in squirting fuel into the carb.Have you cleaned the carb or checked the idle mixture screws to see if they are bent?Did you spray carb cleaner on the connections for the vacuum booster?Have you tested your plug wires? Have you checked the gap on the spark plugs? Compression test?Check oil for water or the water for oil? Cleaned fuse box?

So I reset the timing with distr off. Puts it at like 15-16 with advance hooked up. So I was about 3-4 off and as much as 9-10 off over some intervals.

It's getting low on gas and I've been running Arco for the past 5 tanks. I'll put some Chevron in it today.

The carb is brand new, not rebuilt, 5k miles ago. Motor was rebuilt 5k ago. When I bought it I drove it from Portland no problems. This has only shown up since I reset timing. The previous owner mentioned the timing might be a little advanced so I set it back, apparently too far.

Maybe plugs are fouled now or it's the fuel I'm buying. I buy ARCO deep in the ghetto on my way home and it's way cheaper than other places. Perhaps they are cutting it with something.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Where you buy your gas is not going to make it run or not. Arco isn't so bad a vehicle won't run on it. Many many people only run Arco gas for years, and they get to work on time. I don't think it's a great idea, I don't use them, (I also wonder if it's all rumors about Arco), but I'd bet money because you have Arco gas in the tank is NOT why your truck won't run.

If that particular dealer is doing something illegal to their gas, well that's different. But again, wouldn't you see all their customers on the side of the road a few miles away calling tow trucks?

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OK, I'm over it. Where's the beer?

Set the timing properly first. Should be at 6 BTDC at slow idle with vacuum advance disconnected and plugged. While the advance is disconnected throttle the engine up to about 3000 rpm while watching the timing mark. It should move up the scale with speed increase. Then reconnect the vacuum advance hose and blip the throttle again, the mark should jump quickly about 20 degrees or so advanced. This quickly checks the entire timing advance system.

On edit it sounds like you have the vacuum advance connected to a full vacuum source (not stock) so the timing will advance when you reconnect the hose.

The truck still runs. I drove it this morning 60 mph on the freeway. It just sputters.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Ya, that's how I timed it this time. Disconnected vac and plugged it.

Should I find another vacuum source? I have a vac gauge and I can plug in elsewhere at a diff pressure. I think this one is coming right off the base of the carb, on the cyl head (inner) side.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

[/quote]
Should I find another vacuum source? I have a vac gauge and I can plug in elsewhere at a diff pressure. I think this one is coming right off the base of the carb, on the cyl head (inner) side.[/quote]
thats where mine comes from

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Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

I find they idle a little better and feel a bit more reponsive at the lower speeds with the "ported" type vacuum source. However you have a Weber that may not have a choice of sources. It is not a big deal either way though and probably won't effect the performance problem you are having.

Well I put a tank of Shell 87 octane in and it runs WAY better now. I didn't sputter and I left it in gear up to 4000 rpms to try to get it to go and only when I was getting close to home did I feel anything.

I think they are cutting the gas at that Arco.

You all run 87 right?

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

I work at a gas station.If it has been raining or snowing a lot you can get water in the tanks.The owner/management should be putting in an additive to the tanks to get the water out..but probably aren't.Or they had just received a shipment of fuel and the water got stirred up in the tanks.

my buddy just had the same thing happen with his prelude on safeway gas, put some shell in after pumping the tank and it ran fine.

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Luvless
1980 Mikado-Sold.

1993 Lexus SC400 my Daily
2004 Yamaha WR250F my new love in life
2016 Toyota Camry my girls ride

I missed this thread before, but yeah sounds like classic water in the fuel symptoms. I doubt it is intentional, you just got unlucky and picked some up. No gas station would want to get known for water in their fuel. My 77 had this happen once after a visit to Tillamook Oregon, aka 'The land of many waters' (and massive flooding). It ran awful until that tank got run out.

To clear whatever is left out of the system you can dump a bottle of fuel dryer in the tank. You can also use 99% Isopropyl rubbing alcohol, since it is the same stuff, but 99% can be hard to find, and the regular rubbing alcohol is 70%, with 30% water. Alcohol isn't always kind to the fuel pump though, so keep that in mind, but the water can cause rust which is also bad.

Often times you see water in the gas if you drain the contents of the fuel filter into a clear glass container. If there is water it will be on the bottom.

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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)

MEPR: Man, my 4x4 makes all other LUVs look good

After the new gas, the problems came back. I put STP octane booster in and it didn't help.

So I was going to install an old MSD box I got laying around and I decided to check the plugs first and here is what I found



So I cleaned em up and I'll go run around and see how they do.

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled

Ya it works fine now. Back to Arco gas and time to recheck timing and idle mix.

Do those plugs indicate anything in particular?

Thanks

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1979 4wd Mikado. G200, Gemini 250 Turbo, Clive Cam, Offenhouser Intake, JE Pistons, maXspeeding Forged Rods, Blow Thru Weber, Trooper 5spd, Intercooled