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Engine running rough

Hi All,

Last weekend I finally took the time to fit a new exhaust and a pair of heaterboxes on my 1300 DP engine. Also changed the boots from the manifold along with all the gaskets that go with it. Changed sparkplugs and fitted new wires. The engine ran rough prior to all this and I hoped it would be good after, but with no luck.

What do I mean with running rough? Well when I start the car it runs, the auto choke is working and there is no sputter. However, after aprox. one Kilometer the engine starts to sputter when acc. and it runs real bad. If I don't hit the trottle is will die in seconds. By then the autochoke is OFF but I have the idea the Engine is not hot enough. BTW it is an 31PICT3 with stock dizzy I played with the mixture a little and now I think it runs better but I'm not sure. (haven't really tested it yet). A friend of mine told me that the heathriser might be clogged... could this be the culpritt? Valves, Points? I adjusted the valves and points about 4000 km ago I have a dwell meter but i don't really know how to use it. When installed, the reading is too low (I guess) so that's why I think I'm not using it the way it should be.. I only drive my bug (daily) for a very short distance so the engine can't really heat up properly... but once heated after a longer drive the engine sounds and runs good.

You guys have any idea? Winter is coming and i think it will go from bad to worse.... Please help!

TA Roger

Reply to
bug '59
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Heat riser could make it stumble on accel, but won't cause poor running or dying.

If outside temps are near 10C nowadays and damp, you might be experiencing "carb icing". Heat riser does not affect that very much BUT if you don't have heated air to the carb intake, THAT will allow icing to occur.

If you have the stock air cleaner, check that the flap is set to allow the heated air in (or the thermostatic control is working) AND that the hose to pick up hot air from below is in place.

Forget the dwell meter. Dwell isn't that critical on these engines. If you have the points gap correct, the dwell will be within tolerance.

Speedy Jim

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Reply to
Speedy Jim

Does the 31 PICT3 come with an electric idle cutoff solenoid? If so, make shure it gets 12V. Also the idle circuit in your carb could be clogged. Have you checked your valveplay lately?

J.

Reply to
Berg

Just got back from a 15km trip and I noticed an inconstant idle, even when hot... the RPM where then higher and then lower. By 'carb. intake' you mean the part where the carb. is bolted to the manifolt, right? That part of headriser is cold on mine. If I'm correct this means that the headriser is clogged, otoh, the headrisers left and right felt the same temp (after a half an hour).

I just saw John Henry methode of cleaning... Is it neccesarry to pull the engine getting the manifolt (DP) out?

According to John Muir it sound the same as his next line: a.. Irregular Miss (90 KB) - caused by fuel delivery problems. My problem sounds like fuel problem to me (but I'm no expert)

I have the paper type aircleaner, how can I see if the flap is in the right position? I will check the points gap, hate to check the valves but maybe do that on sunday (cold engine) And cleaning the carb might also be in order... Does it affect the engine when I ditched the tailpipes and use the hollow pipes (without interior) I like the sound of them...

Thanks, (both Jim and Jorn) Roger

Reply to
bug '59

If the idle is drifting or searching, it sounds like you have a vacuum leak. While idling, spray some carb cleaner, WD-40 or about any liquid near all possible vacuum leaks, (Manifold boots, carb gaskets etc.. If the idle rapidly changes when you spray that point, you have found your leak.

Jim SR Racing

Reply to
Jim

Today I took a glance at the engine again. Checked the valves, regapped the points (they were 0.35, now 0.4) Cleaned the carb with compressed air and replaced the stiff (new) plugwires with soft ones from my '59 AGAIN I switched #3 and #4 (You think I should learn)

Once I placed the wires correctly I fired her up again. She ran but barely. Sprayed WD 40 on the boots and gaskeds but no increasing RPM so that's good. The auto choke was already disengaged wich was too soon to my opinion. Opened the choke unit and noticed it was a little dirty inside where the Bi-metal is.

Should I replace it??

The (paper)aircleaner has a flap that works with a vacuum. I'm not sure how to check it's functioning. Sucking on it makes it move so I guess it's working.

Also the left heatriser was getting hot already and the right one was faintly warm... so a blogged heatriser right? And when I drive at, say, 40 mph I can feel a hessitation. Is this related or something else??

Do I have to take out the engine again, or is there a easier way to take the heatrisers out? It is a DP so maybe loosening the boots might help??

Thanks for your earlier ideas, more are very welcome.

Oh, BTW it is not a 31PICT3 but a 31PICT4. Sorry for that mix up

Roger

Reply to
bug '59

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