2000 125hp mercury low rpm need manual

[mebe007]

Hey guys, I have a 20ft angler center console I just got. It's equipped with a 2000 125hp mercury. I know this engine drops 2 cylinders. It really purrs once she's up and going except I can only turn 4600rpm. I'll get to that in a moment. Now I know this motor kicks in the bottom 2 cylinders above 2k. But I'm thinking the transition should be a little smoother. This one is like a sudden spike close to 800 +/- rpm. So I'm thinking it's something with the accelerator pump. Now as to the 4600rpm I know where should be able to turn close to 5240rpm max and at first was thinking a prop change was in order. I'm she's currently running a 13.125" 16p mercury vengeance prop. Was going to throw a 15 on there to see how she did, but kind of want to get a factory manual and check it all over first. Where can I get a good manual, preferably a mercury book? Never had worked on these before I got out of the game. I was just a mercruiser tech.

Thanks in advance guys. It'd be nice to get this center console above 30mph

 

[flyingscott]

The transition takes place closer to 1800 rpm the jump in rpm is pretty normal for them. The ONLY to get is the one from mercury The link and sync for them is kind of tricky. The accelerator pump only makes the transition smoother it sounds like it's working normally. I owned one of those motors and it is still one of my favorite motors but they are different. I would do a compression test and make sure the carbs are opening all the way. If it runs and idles good I would not play with it. The transition happens that way because the cylinders always have spark so when the accelerator pump kicks in it goes. There is no idle circuit in the bottom 2 carbs but they always have spark. What I found out was you need to be smooth on the throttle go right past where they kick in and the transition is almost invisible. If you hang around that 1800 rpm mark then give it gas you will get the jump. Once you get the 4 cylinders running they will stay running down to about 14/1500 rpm. I caution you again on playing with the accelerator pumps or the link and sync. They are easy to screw up and they can be miserable SOBs when you do.

 

[mebe007]

Thanks for the tips. So I decided to check the accelerator pump clearance. I read in piece of a manual posted online as well as the info labeled on my airbox. The accelerator pump housing was bottomed out on the cam. I adjusted to to .030" per spec and it definitely smoothed her out a little more. Throwing a 15p prop on there tomorrow and will see how she does. Did as compression test before I bought the boat. She had 125psi on all cylinders