View Full Version : What RPM to run Mariner 150 EFI.
I have a 1950 Tyee with a 150 Mariner EFI. I was told by the dealer when I start the motor to let it warm up a few minutes and then run it at full throtle. I probably run it at about 3000 to 3500 RPMS most of the time. The dealer said that running it that slow could cause the engine to carbon up and could cause damage to the cylinders and damage the engine.I am looking for some advice. Thank you.
TomD
It probably runs at about 5500 rpm wide open.If you run at slow speeds, you might first decarbon your motor and run something like Ring-Free all the time which is not a bad idea anyway.
Our 150 merc efi we always let it warm up for a bit (3-5-7-8 minutes in april-may in MN, or in October), especially in cold water. Then we get it up to about 3000-3500 for a short bit, then hit wot. In summer when hot we just give it a couple minutes then let er rip, but easing on up to wot.
Has worked great for us. We also troll a lot with it, and no noticable carbon probs. always starts and runs smooth. We use Premium plus oil.
Great motor! :)
-Box
KevinA
03-21-2002, 04:53 PM
Find your self a new dealer.
fishman
03-21-2002, 10:02 PM
If you read in your owners manual it will tell you to run the motor in the upperhalf of the wot range to maintain the durability of the motor. Its in the prop section
KevinA
03-22-2002, 05:04 PM
The reason it is in the prop section is they are telling you to prop it in the upper half of the wot rpm range. The motor will last longest if routinely run in the crusing range, or about 3000-4000 rpm with most large outboards. This is where the motor is running the most efficiently("loafing along") with no coincidence that the torque peaks out in this range & fuel economy is best.
The curves for a 150 will look a little different.
http://users.wi.net/~datuboat/images/img002.GIF