Bought a 86 f350 cutaway motorhome. Just beforeI I bought it another person tried to start it as it sat for 3 + years. Has 100,00 miles, he used ether while cranking but didn't fire. Then I decided to buy and replaced the starter and solenoid, but now barely turns over while boosting. Cannot guess what is wrong, did the starting fluid dry the cylinders?. Should I remove the plugs and add lite weight oil to each cylinder, then see if it will crank?
All ideas appreciated.

 

It probably would be a good idea to remove a few plugs to see if they are getting fuel or if they are dry. Don't remember if they had a manual or automatic choke.
You do realize the fuel in the vehicle is stale and may not want to burn and start the engine.

The one reason I don't recommend starting fluid is because most people use WAY TOO MUCH ! I have seen where it blew holes in pistons or took the tops off.
It can also cause what may sound like a hydraulic lock where the pre ignition prevents the engine from rotating.
How good are the battery and the cables?
.