Is there somewhere I can identify the length of the motor from the serial number?

[briscoe]

I never answered you measure question. The real location is right below the valve cover. Underneath it is the timing chain and and crank shaft, which sits on top of the splined shaft to the transmission. Measure just below the valve cover to the middle of the prop. Looking at your first pictures of your engine, it does look long. That could be 30" as you were indicating. Plus the lower unit looks new. What do you run it in, bath tub water? It doesn't even have paint worn off like salt water and sand erode it.
Also, the run out will be very visible if you have any deviation on the prop shaft (if prop bent it). Not everybody has an indicator dial, but just allowing Prop to turn slowly you will see if shaft's bent. I've never seen a slightly bent one. Even slightly is too much. If you can see wobble, turn out the lights the party is over......

[Mastiff]

briscoe Thanks, then I'll ordre that Skeg Guard if I don't see a warping in the shaft, thanks! I'll try to do another measurement when I change the prop. I was going to do that today, but the weather turned, so I'll wait until I can see the difference between air and water, at the moment they are pretty similar... Can you perhaps mark the spot on a picture for me? I'm not shure what's what on the motor, I'm afraid. Do I have to remove the plastic cover to see it?

As for looking good, the guy I bought the boat from didn't leave it out for longer periods, he tok it up when he wasn't using it because he had his own slip and storage hall (he did commercial pot fishing for small fish that are used in salmon industry to eat salmon lice with it). Also I'm guessing that the cold water up here is a lot kinder on the motors because most lower units look like that here. Oh and finally (like for most people in Norway) fishing and boating season from him was from early May to mid September (when it's legal to fish those small fishes). I have it out all year long because I fish crayfish as a hobby, and that's best in the winter, with cold water. I live on the southern tip of Norway, where the water is the warmest, so open water and larger fjords don't have ice that often in the winter. Where the boat came from, north of Trondheim, the fjords like the one the seller was living in, are passable by wheels, not a keel, from early December to early March.

Moonlighter Mostly because I can buy a used lower unit for the price of that. The quote for taking the boat into the shop and clock the shaft was $700. Everything mechanic is expensive in Norway. It will cost at least $200 to get somebody to spend 20 minutes looking at a car or a boat motor...

tsturm I have friends that live in Alaska, they usually feel very at home in Norway. I just don't know where that housing is...

[Murray]

https://www.harborfreight.com/1-in-travel-machinists-dial-indicator-63521.html

Just a thought

[Mastiff]

Murray Thanks, I found one like that in Norway. But they are magnetic, so it's a bit difficult to get that to work on the lower unit.I will use a slide ruler to chec it, if it's so minute that I don't notice it with that I assume I won't damage the rest of the motor by using it, and then I can get a lower unit when the bearings start making noise.

[briscoe]

Looking at the side view of your engine, concerning your first post. The lowest horizontal electrical wire, is right at the top of your transmission drive shaft. If you separate and lift off the top part of your engine, it exposes the splined teeth to the drive shaft of your tranny. Easy breasey. There is no mistaking a 20" from a 25", which is what I have always seen. I'm sure it's the same if it a 30" shaft. Measure from where that wire is to the center of you prop shaft. Your measurement will be within an a couple of inches. Remember you looking for 5 inch differential between shafts. There is no mistaking the 5" difference between each.

[tsturm]

Measure your transom at the center to bottom of boat, that's the length of engine you should have. If your CAVATATION PLATE is anywhere near the (+/- 1") the bottom of the hull your transom measurement is the length of your lower unit installed. Good luck.
(PS I have friends here from Norway that say the same thing, both places similar)

Or measure this thingy

[Mastiff]

Thanks! For now I may actually be OK. I could not measure any other way, but I cut an aluminum piece to the lengt from the cavity plate to the bottom of the hole in the middle of the shaft, and it did not seem to move at all. So I put on the new prop and took a short trip. Nothing special, except for that the steering is a bit sloppy in low speed. Had to try twice to get in to my dock... But I think that's either because I basically have a missing fin or because I had to tilt it up a bit futher then I usually do. There was a very low tide and I didn't want to mess up my brand new prop by not having any fin taking the sand and pebbles. We'll see when I get my Skeg Guard mid next week.

[Mastiff]

Looks quite impressive, I would say. 20 minutes work laying on my belly on the dock, and now I'm waiting until tomorrow to use it so the red Loctite 263 can harden. I am going to call Henkel tomorrow and ask if I can use it tomorrow, it's very far from 22 degrees C here (more like 5-6), so it won't be fully hardened in a day.

[Mastiff]

Well, the Skeg Gard fix almost lasted a year... Now my lower unit is shot, missing a tooth from the main shaft gear and damage to the bearings. The mechanic says it's almost certainly delayed damage from the impact. So now I'm going to look for a lower unit from the US or UK, the selection isn't that big here in Norway. And getting it repaired will cost me around 3500 to 4000 dollars, which is not an option for something that has 1800 hours under it's belt.