Help with M-2 engine in my Speedster?

[pawngod]

my 00 sportster is doing the exact same thing...revs to the moon out of water and will not go over 2,500 rpm on water.......i ran a compression test and all 6 cylinders have 125lbs psi.....i can live w/that.....i just bought this boat and found a used coil in a compartment...thinking it may have just been changed...it starts first try and idles great. sounds fine..it just wont get up an go.....light smoking ./which i expect...plugs looked clean now what?? its a mercury v6
plugs were buzh8 ngk

 

[pawngod]

i try to read on this subject as i hate bothering people...and find tons of threads of questions w/o them ever being answered, months later even...depressing....do you have to buy in to this website to get even the slightest bit of help? i just need a little help...not wanting instructions for step by step engine rebuild! dont need a page to explain where the oil tank is located...just this one quesition answered! thats all, PLEASE! AND THANK YOU..sorry if this sounds sharp..i am mad at my boat! runs perfect till i put it in the water....thinking my voltage my be bad..yet turns over fast like its has a strong battery...coil is new and not sure where to look now

 

[seadoosnipe]

M-2s........

Sorry for the post going un-answered. Except for those that own the M-2, few members outside of me, have any experience with them. In the forum, we consider them a hybrid.

They are a hard to work on motor with all the electrical protections they have in them I havn't looked up your motor size yet, but these motors can be hell to trouble shoot because you have to have one sensor tell the other that it has this or that one saying it doesn't have that. That's because everything has to check out with the ECM before it'll let you take full throttle.

What I am wondering though, is if your neutral safety switch is bad. It's a built in safety to keep you from starting the motor at full throttle, while in gear, throwing an unsuspecting rider overboard. That would be the first thing I'd check.

There are several threads on the M-2 that I"ve personally answered and solved. So, if your finding unanswered threads, it can't be that many.

You do not have to become a member to get help. But if you were to trouble shoot this boat with me and I told you to check the water sensor or the head sensor, would you know where to look? What I"m saying, is even if I helped you, you obviously don't know enough about the engine to perform the procedures to test it.........

We do have the M-2 shop manual in our library. So, for $10 bucks, for a one month membership can get you that manual, download it and print it. I don't think that's too much for the maual. Then, you can either look through it yourself to find an answer, or get help with members in trying to trouble shoot with you.........................:cheers:

 

[rookie101]

From what I have read one of the most common problems with the Merc motors is the primary fuel pump and fuel filter. It sounds like you may not have enough fuel when the engine is under load in the water. (you need almost no fuel to rev the engine with zero load on it)

Beyond changing the fuel filter you will need some specialized equipment to do an on water fuel pressure test, so unfortunately you may need to take the boat to a shop.



Do to the complex fuel injection system on these motors, without the proper manual and equipment they can be as difficult to diagnose as a modern car. Sometimes the shop can be your best bet.



Aaron

 

[pawngod]

it has the 210hp mercruiser ...no i dont know how to test the sensors...and cant even find the fuel filters any fuel filter...i have traced gas lines and they have been replaced w/black hoses....no visable filters before the carbs that i can see....i guess i will take it to the shop as i OBVIOUSLY dont know enough to get it done..... i got the manual for it on ebay for 4.99 downloaded to the cp....hoping this was a common easy fix...shouldve known better..thanks anyway

 

[rookie101]

If yours is the 210 it eliminates most of the electronics, and makes it a "bit" simpler. Your problem still sounds like a fuel problem to me, but it's hard to tell with out being able to hear the engine.

Does the boat feel like it is starving for fuel? There has to be a fuel filter somewhere, but your boat and engine are completely different from mine. I have the 200 fuel injected merc, so I have no idea where yours would be.

I would have a good look through the manual in the fuel and carburetor sections before I gave up.


Aaron

 

[pawngod]

well spent all day taking out the neutral switch...which was a waiste of time...there is no way that tiny little switch can hinder rev...on this boat...the switch was clean and clearly lets the boat start or not start depending on the position tested it and am positive that it can have no bearing on the engines rev potential...its just a simple switch no chip iin it...what a waist of time.....the old spark plugs looked new but i had never seen anything like them before...they had no electrode ..they sparked against the side of the plug...pure flat across the top..no tip .no gap ..ngk buz8h is the model.......i put in factory recommeded ones ngk..its seems to run perfectly....starts first time by just bumping the starter....revs quick ...till i put it in water.........as i slowly give it more gas it will climb and seem to want to go it just wont rev past 2,500 rpms....can poor plugs possibly cause this symptom? i havent tried it since the new plugs as the closest lake is an hour away

 

[rookie101]

Does the boat start in gear? If it does your neutral safety switch is bad, and that will cause the rev limiter built into the control module to kick in. Normally a bad plug would give you a misfire, but not keep the boat from revving. Any luck on finding a fuel filter?


Aaron

 

[seadoosnipe]

:agree: That's exactly why I thought it may be a sticking neutral safety switch. Because the rpm he's quoting is right at that limit. So, if it was stuck and he put it in gear, the engine would rev no higher than 2500 to 3000 rpm anyway.

Yes, it's a simple switch, but plays a heavy part on a properly running engine.

Next, it's the 210 hp engine, then like Aaron said, it eleminates the biggest part of the electronics, but it still has that daggum electronic enrichment and turn key start electronic control..........which means, it's got to enrichen the engine to start at the right time with the correct amount of fuel to air ratio.