2000 mercury 150 xr6

[Jbchrisman88]

<OT103837>

Hey guys, new to the forums and hope that I have placed this in the correct spot, if not sorry in advanced.

Recently purchased 89 champion bass boat with a mercury xr6 150 on it. The 150 has a surge and would die if trying to maintain a steady rpm for any length of distance like running out of fuel.
I thought maybe old fuel as it had sat for 8 or so months. Drained all the old gas out, noticed a split fuel line so replaced from pickup tube all the way to carbs, took it the the lake same out come. Had it looked at and was told fuel pump diaphragms had busted. Back to the water with rebuilt fuel pump and carbs gone through and synced.
Same outcome.
Had it looked over again and found that the stator or trigger was breaking down, replaced both.
Back to Lake for test drive, she ran alot better with no more hard starts and ran pretty good, except while holding a steady rpm she surges with rpms going up and down while trying to stay on plain.
I can push the key in and it stops surging for a few seconds.

So, fuel system replaced as well as carbs, stator and triger, new plugs.
Also it was oil pump deleted when I got it.
Any help would be greatly appreciated, as me and mechanic haven't had any luck.

[JOE54]

is wrong place look one more down list /if you bump ckoke and problem ceases mtr is running to lean for some reason possible some problem still with carbs not cleaned good

[EuropeanAM]

Fuel system upgrades really need to start at the fuel tank and go all the way into the pulse fuel pump (all at one time, with new filter). No aftermarket stuff, no one piece here, one piece there.

Was a complete sync-n-link procedure completed?

Moving to the correct Forum for you. Please be sure to update your thread with the Engine Serial Number (as required when posting). Thanks!

[Jbchrisman88]

Sorry for miss placing the post, carbs had been gone through 2 times, finally I went through them. I made sure with pen light that all the ports and holes could see light. Never seen any kind of junk used compressed air etc.
Forgot to mention that he had (mechanic) had suspected a reed problem. I watched the removal and install and also inspected reeds my self and gap limits, all looked good.
Thank you

[Jbchrisman88]

The fuel system was replaced all at once after tank cleaned with oem parts from boats.net.
Pickup tube and filter, anti siphon valve, all new fuel lines and primer bulb, hose clamps and zip ties.

Thank you for your reply
Engine model number is : 1150454WD
Engine serial number is : OT103837

[Jbchrisman88]

The fuel system was replaced all at once after tank cleaned with oem parts from boats.net.
Pickup tube and filter, anti siphon valve, all new fuel and primer bulb, hose clamps and zip ties.

Thank you for your reply
Engine model number is : 1150454WD
Engine serial number is : OT103837

[JOE54]

would still look in carbs also

[EuropeanAM]

+1... especially the LOCATION of each jet. Most of these engines have mis-matched jets, and it's pretty easy to get the jets mixed up and on the wrong cylinder (which will cause all sorts of problems, too).

[Jbchrisman88]

Thanks for the replys everyone. I'll have to check the jets and see if they are the same size.
Also took the boat back out Friday, after seeing that the seal at the oil pump block off was leaking, pulled It replaced seals and the problem is just a little different now.
Still stumbles or surges when holding a steady rpm but picks up pretty quick and then back to surging or stumbling but didn't notice that pushing choke in helped this time, at wot it doesn't do this.
Also meant to mention that my compression numbers was 122 to 125 across the board.
As said when I got the boat the engine had already been oil deleted (premix only), maybe a shot in the dark but could the alarm for low oil be causing it to try and shut down through the control module or rpm module what ever its called?
Thanks Guys

[Jbchrisman88]

Also when the sync and like procedure was done by mechanic it mostly just consisted of adjusting the screws on the butterfly linkage to make sure they was in sync.
I'm not sure how to properly link and sync, but I do have a good 4 set of vacuum gauges to adjust carbs on motorcycles, I unplugged the little hoses on the intake next to carbs and connected them, to see what it was operating at on the lake. The top and middle carb was almost identical positive pressure but the bottom was negative (late timing or valves) according to Guage.
I dont know if I'm using it correctly but followed my manuel as best as possible. Other than carb linkage didn't have any other info about syncing. I'm very mechanically inclined so will be doing repairs my self.

Any help is greatly appreciated!
And
Thanks all

[EuropeanAM]

Those ports are for an enrichment circuit, not for synchronizing purposes. They connect to a Thermal Air valve on the STB side cylinder head- the valve is CLOSED (rich mixture) until approximately 100 degrees F (the valve then opens, allowing more air to the idle enrichment circuit and leaning the engine out for WARM operation).

You need a Dial Indicator, a MERCURY Service Manual, a Timing Light and some basic hand tools to perform a Sync-n-Link procedure on this engine.

[Jbchrisman88]

Thanks for the reply, well I was hoping that could have been in but I guess not.
Any other ideas.
This engine is prestine, every bolt still had paint on them and the factory orange stuff for ani tamper for warranty purposes still on it.
I really don't understand what's going on and the reason for so much issue. I know it sat for 1 to 2 yrs. But dog I just want it to run right.....
Any help is appreciated
Thanks all

[JOE54]

do you have a oem manual for this mtr

[Jbchrisman88]

Yes

[JOE54]

would test every electrical ign part as per manual , verify throttle openning and timming arm movement

[Jbchrisman88]

Okay ill give that look Wednesday or Thursday when I'm off.
Thank you.