2001 Dolphin F53 starting problem

If none of this work, there is a 2nd starter relay that is not shown in the engine diagrams for the F53. We had to change ours as we had the same problem. Found out about it reading forums. Took more and more tries to start, then it wouldn't start anymore. We had already done everything else.
It is accesible behind the passenger side front fender with wheel turned or if you have really long arms, thru the doghouse opening from inside. DH was able to change it himself, but it was a chore because of where it is.

Under the hood should be a starter relay. Jumper between the two large posts with a single jumper cable or piece of wire around #6 or 8. This bypasses the contacts inside the relay. It also bypasses the safety switches such as neutral safety switch. Engine should turn over. You will get large arc! If engine doesn't turn over, then the solenoid on the starter it self could be problem.

I did check the connections at the battery, looks like I need to clean them.
Cold & rainy tonight.
Not sure I have jumper cables that long.
Thanks

Likely you have a high resistance point between the battery and the turning of the starter. You can use your jumpers to jump from the battery directly to the starter positive, and a good negative, and if that works you have eliminated the starter as the problem and so it's in between.

Totally check the negative and positive connection to the starter. That is your most likely point of failure if the starter proves to be good with jumper cables.

If it doesn't, likely starter brushes have worn down and need replacing. The springs can't provide enough pressure when the brushes get short, and the starter just burns instead of turns.

Clean and check all connections from the battery to the starter.

My guess is the starter solenoid after that the starter.