I would connect the sender to your ship's wiring and see how the gauge responds as you rotate the sender. If the gauge responds normally, then with the drive down, install the sender in the position that shows drive down on the gauge.
It's reasonable to re-use a six month old bellows. The true answer will be how it looks once removed and cleaned up. There may not be a sealant. If there is it's likely a soft Permatex sealant.
How are you providing water to the raw water pump? Via muffs or drive in a large bucket. If it's a bucket then it's not able to prime since the water level is below the raw water pump.
@cyauch, Have you done a complete backflush of the raw water cooling system? It seems like you have a flow restriction that prevents sufficient flow at high power. Seems to be a common theme with all three overheat at idle threads.
Hate to say it, but you need a new gimbal housing that bolts to the transom. The U-joint bellows seal interface is corroded or broken away and you'll never be able to get a good seal on the bellows. "Luckily", this foregoes the need to remove the seal as you'll need to install a new seal onto...
Note that by drilling out the damping orifice, you may experience more abrupt braking and clunking. It will likely be acceptable, but it won't be as smooth applying and releasing the brakes as it used to be.
Any Volvo SX-M or OMC Cobra SX lower unit with that ratio will work. I believe a '95 or '96 DP-SM duo prop would also work if you can find it, but I don't know what ratio you would need to change to for a duo prop. Someone here would know that.
He's saying that fuses don't protect for positive shorts to ground if that short happens between the battery and the fuse. That's the benefit of placing a fuse close to the battery, reduced exposure to positive shorts to ground. This can also be handled with good wire management/placement, as...
Attwood makes a version without straps that has been working for me for years.
https://www.zoro.com/static/cms/product/prev/CWR%20Electronics%20Corp_59934XL.jpg
