merc help

[Searching4more]

My merc almost sounds like its sleeping, I dont wana say its missing because it sounds like all 6 are hitting they just arnt hitting hard. After the boat runs for awhile it just wakes up like goes from running 4000 rpm to 6000 rpm. The best way i can describe it is it sounds like i hit the nitros button.

[STV_Keith]

What year/power Merc? Have you checked compression? Are any of the plugs darker than the others? What mods have been done to the engine? What boat is it on? What have you tried so far?

[Searching4more]

1989 200 XRI no mods plugs look good 105 to 115 compression. It just started doing this so i havnt tried anything to fix it not sure where to start. All filters are new this year new fuel too.

[STV_Keith]

You need to isolate which cylinders are causing the problem first. Go out and let it do it's thing for as long as it will, then just as it starts to clean out and want to run, shut it off and pull the plugs for a look. The cylinders that have not been firing will be darker and/or wet.
Has the boat recently moved from one area to another? Moving altitudes (different lakes) can play a factor in jetting.

[Greg_Moss]

Kieth the XRI is a EFI motor. Most likely it's the ignition system. does you tach show what you are saying? is it really pulling to 4000 then taking off and pulling up to 6000? you still need to check and see if any of the plugs show a misfire. check all your grounds and ohm out the stator that is a high heat 40 amp stater and it could be your problem.

[STV_Keith]

If it's EFI, have you checked fuel pressure?

[Searching4more]

Yes its a efi motor. Yes the tach shows the rpm jump and if you are standing up in the boat it will put you in the seat. I ahve no idiea how to check anything cept the plugs and they looked good. To me it doesnt sound like a mis because the motor runs smooth just not all there, unless a mis inn a 2 stroke sounds like that.

[Greg_Moss]

I wonder if the timing advance module is acting up somehow? I have one of those motors here let me go look at what wires you can unplug and I'll post back for you to test it.

[Searching4more]

Thanx man anything i can test i will this weekend. I keep the boat up on the river. Is there a high speed winding to check? I have been looking around on the forums reading and ran across someone talking about a high speed winding or something like that.
Also I just left the prop shop I tried a 24 pitch with some bite in it it worked well when the motor was all there. I told him I was 1 and a half inches below the pad and he told me to drop it a tad before i try anymore up, its a vee hull and i have read 1000 times to have the shaft even with the pad. Is he nutz?

[dschifan]

its probably the ecu, i have a 200 merc xri as well and it did something real similar. it would kinda bog and then it would just pop and take off and run to its top rpm. before you beat yourself up looking through cylinders and stuff, check the ecu you might need to get it rebuilt the xri motors are notorious for having ecu problems.

[Boatmaster]

I would say a lazy ECU or switch box. I would lean towards a switch box, only because the ECU normally has a motor dying like the key was cut.

[Greg_Moss]

first thing to check is the high speed spark advance module on the switch box you will see a red with a white stripe wire and a white with a black strip wire coming from the harness leading to a black box on the port side of the motor those wires should have plugs in them about 6" from the switch box. disconnect those wires and go try it again.

[Searching4more]

OK I'll try that. What is that going to do? What should i look for after i unplug it? Dempending on what it does what should i do next? Thanx for all your help guys.

[Greg_Moss]

if the motor runs right without it plugged up leave it unplugged and have fun with your boat. It is a module to adjust the timing at idle and over 5500rpms by varying the bias voltage to the switch boxs. You don't need it best to dump it set your timing to 155 thousands and go for it.

[Searching4more]

Thanx greg now lets say that dont work, plug it back in and check something else?
I have never timed one either guess I need to do a search on setting timming. I guess a basic timming light will get the job done?

[HavasuBarney]

One thing at a time Search, it's a process of elimination.
What up Greg. you're a stud dude!
:)
I was thinking if that don't work, should he invest $2,000 in a billet running table on wheels?

[Searching4more]

Just think how many questions i would have to ask with a runnin motor on 2k worth og billit on wheels.

[Searching4more]

I made it out this weekend to try unpluging the high speed mod and it didnt work. Today it didnt even try to run right still doing the same thing. It had no spunk at all, if i had to pull a skier it wouldnt have happend. It will get on plane but never runs right. I did notice that the fuel ball never got hard or stayed hard.
Some pics of the Boat,me and wife
www.putfile.com/uoshane

[Towndrunk]

I have a drop on 2.5 245 runs good. $3500 & shipping. 623-256-9759

[Searching4more]

Wish I could TD but aint got the cash I am just gona have to fix this one.
You guys that had seabolds.............did they have a core?

[Greg_Moss]

Mark your flywheel at each cylinders TDC. Label them 1-6 and see if they line up with your timing pointer as the motor is running. Make sure your not double firing. You should be able to see each cylinder fire with your timing light. If you cann't then you have issues with the trigger or switch boxs. most likely it will be the trigger.

[Searching4more]

To find TDC........do i just look at the piston and when it hits its highest point in the can is that TDC?

[Greg_Moss]

yep