Synthetics are great but imo un nessecary. Any outboard maufacturers oil is plenty good, because it has to be approved by them for them to warranty the motor if it fails. I recommend not using pennzoil or westmarine oil, but you can use whatever you like. I personally run the Quicksilver premium plus oil at $18.99?? (havent bought any in a while..) a gallon at wally world
i've almost exclusively used pennzoil xlf without trouble but i recently switched to tohatsu brand just for peace of mind. BTW if y'all have motors in the serial range for the recall I would recommend getting the warranty fix. I had some minor issues with not being able to crank after long runs until the motor cooled off a little but no problems anymore!
I dont know if there was an actual recal but I do know many 40/50 tohatsu TLDI motors were having vapor lock issues. Owners were experiencing issues starting the motor after long runs on hot days and or starting the motor after it had been trimmed up a long time. I heard that Tohatsu's solution to the problem was installing an external fuel pump near the fuel tank and re-programming the internal computer.
This is why i asked rummya what the warranty worked entailed. Im intersted to see what the solution was and if it had worked so far.
I was originally interested in re-powering my skiff with a 50 TLDI but all this scared me away and I have yet to be convinced/feel comfortable to buy one. I even spoke to a Tohatsu rep at the boat show and you told me hands down that if I fished in south fl in the summer that I would experience the problem and the only existing fix was to install external fuel pump. I am not willing to fork over 4 plus grand to then have to have warranty work done.
the work involved changing the air injectors, fuel injectors, reprogramming the computer for the new injectors, and installing an external fuel pump to keep the pressure up. I was having the exact problem that you described, it would take a while for the motor to cool down before it would crank up after long runs or being trimmed up but now no problems whatsoever.
i started doing that myself and it does help, but there is no replacement for a properly working motor. There are times when I need to shut down asap and its nice to have the motor crank right back up again.