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Old 11-14-2004, 07:42 PM   #1
Mudboat
Scooby Newbie
 
Member#: 74616
Join Date: Nov 2004
Default Need help/ideas

I have a 1800 engine (1982 - 84) in a mudboat. These are popular down in South La. for hunting the marsh.

The engine runs great for about a minute once I'm hooked up on a plane, then it sputters out and kills. It re-starts right away and I can let it idle for about 30 seconds before taking off again. It will run for 30 seconds or so and sputters out again. In summary, I can't keep it running at speed for more than 30 seconds to a minute at a time. Here is what I know about the engine:

1800cc
Carter/Weber TYF type 1bbl. carb.
Electronic ignition

Here's what I did so far:

New Dist. cap, rotor, coil, plug wires, plugs, fuel filter, cleaned fuel tank and cleaned out carb. I suspect a bad pickup coil or some foreign fuel problem like the fuel pump, but it maintains a steady 4 psi pressure.

Can someone help me out with troubleshooting? I'm tired of changing good parts...

Thanks in advance...
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Old 11-14-2004, 07:47 PM   #2
Mudboat
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Member#: 74616
Join Date: Nov 2004
Default Update

I replace the fuel pump today with no improvement. I also pulled apart the top of the carb to check the float valve. Re-assembled and went launch again. No improvement.

I just ordered a remanufactured carb from Roo-Builders (TYF-7629S) for $300 and some change, shipping included.

I still suspect the ignition pickup as well, but I will worry about that if the new carb turns out to be a bust...

Still looking for opinions or suggestions.

Thanks..
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Old 11-15-2004, 10:16 AM   #3
camshaftprelube
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Member#: 54415
Join Date: Feb 2004
Chapter/Region: MAIC
Location: Virginia
Vehicle:
A strange
Tercel attraction

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I would've gone with a weber 32/36. It does sound like a fuel delivery problem.

Vacuum advance working properly? This might cause a loss of power at high rpm.

Is it possible to back out of that order you made? I've never heard a good thing about that carburetor.
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Old 11-15-2004, 01:36 PM   #4
hartage
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Member#: 71141
Join Date: Sep 2004
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I've been doing a bit of reading on 82-84 1.8l seems it's a carb controlled by an ecu and o2 sensor. It compares the air fuel values from the O2 to what is stored in it's memory. It then sends a signal to a solenoid at the carb to either restrict air or increase air to adjust air/fuel ratio. Your engine has a thermo switch that keeps the engine in closed loop(ignores o2 values)untill it warms up then goes into open loop (reads o2 values).

I would check on your o2 sensor and see if it is in good working order. You can check it with an o2 sensor reader, or you can use a multi meter (voltage). But be careful to use only a multimeter with a high megaohm value. (one that does not put a drain on the tested line, 20megaohm is good) If you use a multimeter or a volt meter that places too much of a drain on the o2 sensor it will blow it.

It prob would help you to get a manual on your engine. The better you understand how your a/f ratio is controlled by your motor the better chances you have of finding the problem. Good luck.

BTW, I'm not there so I'm only pointing you in the right direction, not telling you it definately is the o2 sensor. But if it happens only when warm, but it still idles properly that points me to your open loop a/f system. Most likely o2 sensor but test it before you replace it.
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Old 11-18-2004, 11:13 PM   #5
Caboobaroo
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Member#: 72335
Join Date: Oct 2004
Chapter/Region: NWIC
Location: Oregon City, OR
Vehicle:
89's RX/XT6
Blacksssssss

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Quote:
Originally Posted by hartage
I've been doing a bit of reading on 82-84 1.8l seems it's a carb controlled by an ecu and o2 sensor. It compares the air fuel values from the O2 to what is stored in it's memory. It then sends a signal to a solenoid at the carb to either restrict air or increase air to adjust air/fuel ratio. Your engine has a thermo switch that keeps the engine in closed loop(ignores o2 values)untill it warms up then goes into open loop (reads o2 values).

I would check on your o2 sensor and see if it is in good working order. You can check it with an o2 sensor reader, or you can use a multi meter (voltage). But be careful to use only a multimeter with a high megaohm value. (one that does not put a drain on the tested line, 20megaohm is good) If you use a multimeter or a volt meter that places too much of a drain on the o2 sensor it will blow it.

It prob would help you to get a manual on your engine. The better you understand how your a/f ratio is controlled by your motor the better chances you have of finding the problem. Good luck.

BTW, I'm not there so I'm only pointing you in the right direction, not telling you it definately is the o2 sensor. But if it happens only when warm, but it still idles properly that points me to your open loop a/f system. Most likely o2 sensor but test it before you replace it.
It all depends on the carb setup also. Depending on the carb and where it was made (ie California) and whenever this was in either a 2wd or a 4wd car. Some had the computer controlled carb, some didn't. Like I said on the USMB, just get a Hitachi carb and manifold and swap it over. You'll have less of a headache in no time
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