couple of questions.

brunolund

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Jan 26, 2008
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96 4.3LX merc alpha 1 gen 2

1. which temp sender do i need? i have a guage and an alarm, but wwhen i replaced the one for the guage, it still doesn't work. when i ground out the wire, it pins thye guage over to the right. i used a sierra guage, as thats all that's in stock in my area. part number- 18-5897 which the catalogue says replace # 97257A1. it also says this does not include the dual application. but it is the only one listed with the correct thread. could someone tell me if i'm correct, or which part number i need? also is there a way to test the guage without running the boat? currently i'm waiting for my lower to come back from the welders. when i was running the boat, the guage would read about 100 degrees. it would move very slightly when the key was turned on( or the wire was removed), but it would stay there all day. my engine feels as though it's getting warm, yes i know that's means notrhing without a number, but it is definitly warmer than 100. i think i have the sender for the alarm.

2. is there a way to change my tilt trim switch? it is on the throttle lever, and works, but is not right. i have to pull the bottom out for it to go up. i felt it pop a whil ago, and want to fix it now. it is a lund tyee.
 

brunolund

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Re: couple of questions.

fixed it. thanks for the link. any tips on the sending unit?
 

Don S

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Re: couple of questions.

You didn't use teflon tape on the threads did you?
 

brunolund

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Re: couple of questions.

no, but i just removed the old one and measured the resistance( at room temp.) and it was 1.600 Mohms this sounds extremely high. so i figure it is shot. now i've got to try finding a new one. any idea of the correct part number?
 

Don S

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Re: couple of questions.

The old number was 97257A1, but was supperceded to 806490T.
And it does cross to the Sierra number you have.
You also don't want to over torque them or you will destroy them. It's a pipe thread, and super tight is not necessary.
 

brunolund

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Re: couple of questions.

now i'm cofused. is the same sending unit used for the guage and the alarm? i i thought one owas variable resistance and on was basically a swithch? how would i test to see if this is correct? would measuring the resistace while warming the sending unit in a pot of water work? or is that not a good idea?
 

Don S

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Re: couple of questions.

now i'm cofused. is the same sending unit used for the guage and the alarm?
No, they are different units and work different. The sender changes resistance when it gets warmer. But will NEVER show the 1.600 Mohms that you said you have.
At room temp, you should be seeing something in the 100 ohm range more or less. If you are seeing mohms, then you either have a switch or it's a broken sender. What color wire is going to it?
The switch is part number 48952.
 

brunolund

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Re: couple of questions.

well now i feel dumb.the reading i was getting on the sending unit for the alarm was actually the reading through my body. turns out iwas holding the probes with my figersa touching metal part of the probe(DOH!). done properly, i have no continuity throught the sending unit, which tells me it's a switch.

now for my other problem. i do have the right sending unit, it does change resistance when warmed. i figured out why my guage wasn't reading properly.
turns out the thermostat housing doesn't have a clean "connection"to the rest of the engine. i used the marine gasket on the bottom and an automotive one on top. i don't remember seeing those metal contacts in my marine gasket, and i'm sure there are none in the auto one.

resistance thruogh sending unit when at room temp- 660 ohms
resistace through gasket and silicone- 700 ohms
2 hours to figuyre this out(this time)- STUPID


oh well, i do feel better cause i know the fix. finally.

thanks don
 

brunolund

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Jan 26, 2008
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432
Re: couple of questions.

thanks. once i get the correct gasket, i'll see if it works.
 

Electroman1

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Re: couple of questions.

I'm new here. Where do I find the password for the above referenced pdf? Thank You!
 
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