1998 merc 115 runs on two cyl only to 1800rpm

[micknmerle]

my 1998 merc 115 has a 2 + 2 system (2 clinders only till 1800 rpm then all four work) it has no idle screws on the bottom 2 carbs. It is most annoying now that my little girl is learning to ski, as it has a real spike in acceleration when it gets to 1800 rpm. Has anyone heard of a solution to this ? Or any other ideas?

Thanks Mick

[blaze]

Re: 1998 merc 115 runs on two cyl only to 1800rpm

Hi Mick
I also have the same outboard, bit earlier though, can also be a pain when trolling. No fix. Wonder if you proped down abit for sking, may help. I know when I was playing props I put a 15p on and it got out of the hole like a shottie going off
cheers
blaze
ps
welcome to the chatboards, great place and exelent knowlege base

[micknmerle]

Re: 1998 merc 115 runs on two cyl only to 1800rpm

yes i agree blaze.. it is just the annoyance factor. i have a 17 foot carribean safari and i'm running a 20'' laser 2 prop which is still under propped as i can still hit the rev limiter at wot with next to no trim and the whole family and gear on board.
The motor is also tempromental when hot and will stall at idle in gear (usually when u are about to drive onto your trailer)

I'm wondering if the carbs can be modified or maybe i should hunt the wreckers for carbs off a later model( I dont think mercury continued with this setup) Do you know if the 125 hp model was the same setup?

[dfox]

Re: 1998 merc 115 runs on two cyl only to 1800rpm

G-day mick, i too had one of these engines for a number of years. Apart from the carbies the engine has a two stage stator setup, this may present a problem as well.Im no expert on this but i do know that the first stage operates the engine at low revs and then as the four cylinders fire the main stator takes over. I had alot of problems with my engine due to the fact that this first stage stator would burn out while out fishing while i was idling around with the sounder on. The engine would run fine but after it was turnt off it would fail to start again, (a great feeling 60km off shore). The design fault was eventually fixed with an updated version of the stator with heavier wiring, but not after i burnt out 4 of them. The bad stators are painted black and the improved version red.
In theory the system of running on 2 cylinders at low revs and conseving fuel sounds good but in practice i dont like it. I,d guess that the 125 being bassed on the same power head is most likely the same. Id suggest to save your money and just use it like it is, when it warn out buy something better. I lost faith in mine and traded it in on one of its bigger V6 brothers....foxy