1987 Other Mitsubishi Models Carburetor?

AMPHIBIAC

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1987 MITSUBISHI

Engine Performance problem
1987 Other Mitsubishi Models 4 cyl Two Wheel Drive Manual 121xxx miles

Truck has new plug wires, plugs, PCV valve, air filter. Runs rough, seems to be running too rich. Black spatter from tailpipe. Wants to stall when half warm, runs pretty decent at startup and after fully warm. Timed properly. 2.0L engine. Takes a long time to warm up. Any ideas?

3 Replies

JAMES W.

MECHANIC
2,394 POSTS

The basic control system for your carburetor is the O2 and engine temp sensors. If the engine takes a long time to warm up, check or replace the thermostat. Running too cold will make it run rich. If that doesn't solve the problem, you may want to change the O2 sensor. There is really no accurate way to test them.

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Wednesday, December 31st, 2008 AT 7:35 PM

AMPHIBIAC

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James,

Replaced thermostat and O2 sensor, no change. I think the fact that it's running too rich may be keeping it from warming up. To me that means the problem lies elsewhere, very possibly in the carb. Care to try again?

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Wednesday, January 14th, 2009 AT 8:59 AM

JAMES W.

MECHANIC
2,394 POSTS

A lean motor does run warmer than a rich, but in a 4 cycle engine it's not that noticeable. A 2 cycle is a whole different deal. If you over richen a 4 cycle, they just flood and quit. Where as, a 2 cycle will burn up. Anyway, to adjust the idle mixture on your carb, you have to take it off, turn it over, drill a hole in the bottom to knock out the plug seal, and then you can get at the mixture jet. You'll see the plug in the front of the base plate.

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Wednesday, January 14th, 2009 AT 8:44 PM