Pair 2.5 260 efi 17 hrs

**norm10_10** · 06-27-2017, 11:29 AM

Just bought a 22 eliminator with a pair of 2.5 merc 260hp efi's with 17.7 hrs. The motors and boat are 1996 models been in storage for a few years. Hit the keys and they fired. What would be the recommended oil and plugs? Live in Canada and the merc racing oil is hard to find. I will be changing lower oil and fresh fuel. Any other suggestions? I'm much more familiar with 3.0 stuff. What to watch for on these motors?

**Scottko** · 06-27-2017, 12:16 PM

I personally like Amsoil Dominator. It's a full synthetic racing oil that can be used as pre-mix or injection. Red in color, easy to i.d. if the fuel has been mixed, and it smells good. I'm sure you could get a bunch of opinions on oil. I also like Klotz, but that's harder for me to find around here.

Not sure on the spark plugs, someone will probably chime in on that. But you may want to replace the water pumps if it's been sitting for a while.

**J.R.** · 06-27-2017, 03:58 PM

semi -syn for those steel cylinders and full syn for Nics

**Scottko** · 06-27-2017, 10:36 PM

Originally Posted by J.R.

semi -syn for those steel cylinders and full syn for Nics

Forgive my ignorance, but I have never heard of this before. What is the reasoning behind this?

**whipper** · 07-03-2017, 01:47 AM

Scottko This was the tested reason for many years. Ill give it a shot as to what the reasoning was or maybe still is for some. With steel bore motors there are pores not smooth like Nic sleeves are. Blend oil like PremPluss stays in the pores longer and was tested to have better lucubration than full Synthetic for steel bore motors on premix. Or something like that lol Im not sure if this is still the case any longer with the advancement in {some}synthetic oils today. For instance the zinc content in Amsoil is quite high and that seems to be a good oil in alot of steel bore motors today that have lived for years and hundreds of hours with no problems. So the old school of thought may be debunked with some of the newer formulas i do not know??? But I am about to find out haha Im going to switch to the HP injector because of cost of Prem Pluss now. It is not affordable to run for me and the Amsoil is. I have heard from many steel sleeve motor guys with hundreds of hours at high rpm with zero failiers so Ill take the chance on what seems to be working for people I know and trust today.

i have been a faithful merc prem pluss and merc oil user for almost 40 years since my first outboard a 50 merc when I was 14 years old. 13 years with my 225pm with the same pistons and rings. So for me to change now seems drastic but Im convinced from what i have researched that petroleum based oil is not getting better but synthetics are.

**patchesII** · 07-03-2017, 04:50 AM

Change the water pumps and, if it were me, I'd change the fuel lines too

**norm10_10** · 07-05-2017, 08:25 PM

Changed the pumps. Running at 140 on the temp. port motor running 800 on the egt and tack bouncing at the same time the livorsi gps bounces. Could this be a rectifier. Port motor doesnt idle well. Ran 109 and port motor cut out. Seems like an electrical issue.

**norm10_10** · 07-07-2017, 11:58 AM

New rectifier working like it should. The boat is a 22 eliminator with speedmaster 2.5's the efi boxes are -9's 8400rpm Motors run at 140 degrees on the guages don't get any hotter regardless of rpm. EGT on port motor 900 and starboard is reading 1250 1300 degrees. If I mash the gas at 4500 sartboard temp comes down to 1200. Even at idle it runs 600+degrees plugs have been read and look good, pistons look good as well. What would be the correct ohm reading on the egt prob? Livorsi guages.