I have been looking for another temp gauge for the boat so I can monitor both banks of the engine. The gauges I have are NLA (OMC). I just found a new old stock gauge and sender on e-bay. I already have an oil quantity gauge that needs to be removed because I dis-abled the oil injection system after losing a power head the first year, so I have a place to put it. jim
Jim, You "dis-abled" the oil injection system?? I guess you mix your oil now? What ratio do you use? Kevin
50 to 1. I have done it for 11 seasons now. This practice is common with the Mercs in a high performance application because the oil injection pumps would not take high rpm. The motors from the race division did not have oil injection. The high performance Opti motors do not turn the high rpm. The 2.5 EFI on my mirage would turn a 28 pitch chopper prop 9000 rpm. That motor and its derivatives were built through the late 90's and never had injection. They run on 32 to 1. They turn them 11 grand in a drag race application. jim
Thanks Jim. I'll be back to mixing my oil and fuel if I can get my Merc 1500 to run. Went through 4 gallons of Opti oil this past summer. I'm not exactly sure how many tanks of gas we went through as I heard that junior and his friends made "extra, undocumented" trips to the marina for fill ups!! Kevin
4 gallons of oil at 50 to 1 would be 200 gallons of gas, but, that motor probably runs much leaner than that. I would guess that you burned 300-400 gallons of gas with that much oil. I guess you will find out when you get the bills. I would use Mercs premium oil in that 1500. It has gotten quite expensive, but it is better than buying power heads. jim
Yes I agree. I use Mercury Premium Plus oil in mine, I run it at 50:1. I also change the impellers every 2 years, more often if I use it at the river do to higher sand and debris content. Daniel
Good idea on the impeller Daniel. The Merc impellers like yours were used on the 2.5's until recently and they were not long lived. Merc has gone to a much larger impeller similar to the OMC. It was introduced on the 3 liter motors and even the 75 hp has it now. It is a bunch more rugged. It is a bad idea to push the life of an impeller. If they disintegrate the pieces get trapped inside the cooling passages and even with a complete tear down they are hard to find. It only takes a few seconds of running dry to destroy one also. jim
