Heat Risers

Dec 16, 2003 2 Replies
J

My 66 1600cc VW Bug has been having problems in the cold recently. It has a tendency to stumble from 1st and 2nd gear and overall sluggish performance until it is fully warmed up. I've changed the carb, put new plugs (gapped at .70mm), adjusted the timing and replaced the inline fuel filter(electric fuel pump). The only things left are the valves and the cleaning of the heat risers. I put my hands on the hear risers before the elbows on the muffler side and they're hot. When I touch them after the elbows, they're cold. It sounds like this might be the problem. Has anybody experienced this? Can I just remove the muffler and clean them from below? It seems like a major job to get to them from above.



Thanks, John


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S

Yes, lack of manifold heat will cause stumble in cold. With muffler off, you can run a snake thru or just try compressed air to see if it's open.

They can be tricky to make work. Many replacement mufflers are junk; the pigtail tube on one side may be kinked or not lined up with the center of the exh tip. Sometimes the ports on the exh flange are blocked with weld, etc.

Tailpipe insertion depth matters too; experiment with that.

Speedy Jim

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M

Also, what aircleaner are you using? A stock unit should have provision for a warm-air pickup.

Max

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