View Full Version : Spark Plug Opinions for fuel injected motors
I am running a 225hp Yamaha EFI and when it get rough on a big lake like Lake of the Woods I use this engine to troll and when I go back in it is hard to run the motor over 3000 rpm because of how rough it is. The plugs are starting to get oil fouled and prior to owning this motor I had a 150hp Yamaha carb model and never had the problem. Both the 225 and the 150 I would cruise at about 3200 rpm which is about 30mph and I did not run the motor wide open alot The 225hp is running NGK BR9HS-10 which to me seems to be a cold plug. My 150 was running BR7HS-10 which is a hotter plug and I think they were in the motor for two or three seasons and they looked fine when I changed them. I was told that the dark oily colored plugs in my 225 looked fine for a fuel injected motor. How do your plugs look in your fuel injected motors and has any one tried going to a plug which is one heat range hotter. Or am I asking for trouble.
Mike from Wisconsin
08-15-2001, 08:24 PM
I have an 200hp Optimax and my plugs look like that and the dealer said that was normal and I thought about a hotter plug. But with all the problems with the Optimax I think I might leave it alone
Mr. Pike 17
08-18-2001, 04:17 AM
You're asking for trouble by jumping heat ranges. I would suggest using a quality synthetic oil like Amsoil and running some Seafoam through a tank of gas to take care of your fouled plugs. Trolling with a large 2 stroke will always cause plugs to build up with carbon and other deposits. Ever since I went to the Amsoil 2000 Series Racing Oil, my plugs are very clean looking. Every engine is different. I also use the NGK Platinums in my Optimax....
PJM, Plugs are fouling when the motor starts running bad. You describe it when your plugs look fouled. If your motor is running fine (and I think it is) leave your motor cover on and your tool box closed. Keep fishing Tom
FROGMAN
08-18-2001, 07:43 PM
I'm afraid I must be of the desenting opinion here. I have run a Yamaha 225 V-Max all year on the circuit, and have found a couple of tricks that will help you. First of all the Yamaha motor has a variable rate oil injection system. At slower idle speeds it is possible to load them up, they don't like to be idled for long periods of time. Second have a technician check, and perhaps adjust you oil injection settings. If they were originally set rich for break-in perhaps they have not been leaned out yet. Thirdly I would go with one step hotter plug. I run the 8 series NGK (BR8HS-10), and have had no problems at all since switching. Good Luck, and let me know how things work out.
Keith Segar
NPAA #260
Keith
after reading your reply I think I will try one heat range hotter. As you know the 225 EFI had an OX sensor and if it the get plugged, the motor will run bad. I did have the oil pump adjusted and that did help but the way I run my motor I think a hotter plug will help. I will try the hotter plug but I will keep keep an eye on it. Yamaha runs the BR9HS-10 which is a cold plug in the big outboards because I think its designed for running wide open which I don't run alot. It looks like you tournament fish so and if you idle your motor alot those BR9HS plugs must have look like mine. I value your opinion because your on the water alot. I would like to thank everyone for there input also..............