Mrmerlin

you dont have to drain the oil,
but some oil about 3 oz will come out of the sender when its removed.
When you install the new sender use a bit of Loctite PTFE pipe sealant on the threads as well as a new sealing washer

JPTL

Ah, that's what I want to hear!

depami

Don't bother with used. A good new one is under $100. A crap new one is under $50.

Had that boat out tonight. It is awesome! It doesn't ride much higher with just me in it.


Edit:

Call Roger or the like.

Or, go here:

http://www.pelicanparts.com/cgi-bin/...&I1.x=0&I1.y=0

worf928

It's certainly true that they don't swap themselves. 50/50 shot when you put the new sender in.

As per Stan: make sure you use new crush rings. Don't skimp: you'll end up damaging threads or have a leak.

The sender is easiest to get out using crow foot wrenches. Else, you'll need to get the alternator out of the way.

JPTL

Checked the wires per Denny's notes (thanks Denny) and they check out - most importantly, the gauge goes to 0 when its wire is grounded.
Then I checked the resistance between ground and the disconnected gauge post per this thread and I got nothing. No continuity whatsoever. Hopefully I'm dong this right....I assume that there should be some continuity between the post and ground - whether the unit is wired or not, right?
According to Techno Duck, the reading between ground and the gauge post "...should be 180ohms on a cold engine, around 70ohms on a warm engine. If you see over 200ohms the sender is bad."
Nothing with engine off or engine running.
So it looks like a cooked sender.

Thanks for all of the replies/suggestions!

dr bob

The sender is actually a transducer that meters current, so that minor changes in wiring resistance dowsn't mess with the reading. So your simple Ohm meter test, especially with a modern DMM, may not pass enough current through the sender to get a valid reading. You can experiment with a 9V battery and a resistor, and measure the current flowing through the sender at different pressures. But you are going to replace it anyway, right?

FredR

This post prompts me to ask a question related to the subject matter. I have some issues with the wiring harness- fact. I have temporarily patched it up after replacing the sender but the needle on the gauge is a bit jittery and what has me more concerned is that when hot the indicated pressure is lower than it should be or at least lower than it used to be. The pressure when cold hits 5 barg when cruising but when hot it drops to an indicated 4 barg. This has me worried should this be a correct reading- any thoughts as to whether it may just be a false reading due to the wiring issue?

I cannot detect any funny noises or performance issues.

Regards

Fred