Merc 150 XR2 problem

[whiplash921]

I have an interesting problem that I have been working on for quite some time. My merc 150 xr2 will stall out when the motor is lifted while in the water. It isn't trimmed up so high that the prop is out of the water, but it is trimmed up to the point where the high speed on the trim motor kicks in. When it gets to that point, the motor will start to cough and act like it is running lean, like a gas line is getting pinched. I have checked a lot of things and poured a ton of money into this motor, not just for this problem, but the carburetors have all been cleaned, new needles and seats, made sure that the floats were set right, just getting frustrated. On a possibly seperate problem, when I go to get the boat on a plane, if I do it slowly, when the motor gets to the point where it's very close to taking off, and I'm plowing through the water, it will cough and die there as well. Not sure if these problems are related or not. It will do the same if I'm trying to pull a skier, obviously I'm not trying to get on a plane slowly there. Please help, I'm going on a fishing trip the 2nd week of August and this thing has to be running perfectly.

 

[studlymandingo]

Re: Merc 150 XR2 problem

Sounds like a carb issue. From what you describe it sounds like a needle not seating properly. You mentioned new needles, are your floats adjusted properly? Could also be that the needles are not adjusted properly.

Has the fuel pump been rebuilt?

 

[whiplash921]

Re: Merc 150 XR2 problem

I'll have to check to see if the needles are in properly. This is my brothers boat, and he replaced the needles and seats, so I'm not sure. He said that he followed the specs in the mercury service manual, but I still better check it out. I personally tore the carbs apart and made sure that everything was clean, jets and so forth, and I adjusted the floats according to merc spec. As far as the fuel pump goes, I don't think it was rebuilt, but my brother did say something about replacing something, but I think it was just the gasket.

 

[knotready]

Re: Merc 150 XR2 problem

i would look more at fuel supply try a gas can eliminate all fuel lines and tank i had a 1986 offshore 19ft cleaned the tank replaced all lines filter housing pump the pickup tube in the tank had silicone blocking th screen in the pickup tube simple fix cost alot of time and money

 

[whiplash921]

Re: Merc 150 XR2 problem

I will try that as well. Thanks, I'll let you know if I find anything.

 

[whiplash921]

Re: Merc 150 XR2 problem

I heard one suggestion that the mercury kill switch might be faulty. Do you think this is possible? Sorry, I have been away from this boat and haven't had a chance to do anything to it. I am going to work on it tomorrow. I will try the simple things first and let you know. Thanks again.

 

[jebeebe]

Re: Merc 150 XR2 problem

I would think it would kill it outright, unless it is just arcing and not enough to kill it completely. You could try to tilt the switch a little toward the virtical and try it .....................Jerry

 

[gss036]

Re: Merc 150 XR2 problem

Does you motor by chance have a mecury type tilt/kill switch on the motor?
I am looking a 1989 OEM wiring diagram for 135-150-175 and it shows a Mercury switch that goes to both switch boxes and eventually goes thru the wiring harness to the dash.
Could be that when you get to a certain trim level you loose power to the iginition system which shuts down the engine to prevent damage.

 

[whiplash921]

Re: Merc 150 XR2 problem

Ok. I have decided that this is not a problem related to engine position, well not entirely. I finally got a chance to run it today and I think it is actually an electrical problem. I pulled the carbs apart and adjusted the floats to allow more fuel into the engine, but that turned out bad. While it was running I could see fuel dripping from the carbs. So, I pulled them back off and closed them up a little, fired it up and it sounded a little better. Then I noticed that there was an intermittent miss at idle. I pulled the plug wires off one by one while it was running (was using well insulated pliers) and on one bank, cyls. 2, 4, & 6, I was getting massive spark when the throttle was higher. Don't ask what RPM cause my gauge isn't working right. On the other bank, 1, 3, and 5, I had a hard time seeing any spark between the wire and the plug. If I was idling, I could see spark all the way around, but cylinder 1 seemed a little weak. Anyone have ideas? I was thinking maybe the switch box, or maybe the stator. My only question about the stator would be that shouldn't it miss or have a weak spark on random cylinders? Since it's 1, 3, and 5 would that more than likely be the switch box? Please help, dead line fast approaching!!

 

[whiplash921]

Re: Merc 150 XR2 problem

Ok. I think I have a bad stator. I haven't run through the test yet, but after I switched the switch boxes I decided to switch the stator wires too. The problem moved after doing so. I am about to go through the stator test and we'll see what happens from there. Hopefully I am close on this.

 

[whiplash921]

Re: Merc 150 XR2 problem

I did the ohm test on the stator, and it read good. Is it possible that it could still be bad? I changed a couple things around, such as the switchboxes, and the bad condition stayed on the same bank. I did the ohm test on the trigger as well, and it checked good. I pulled the flywheel off and there were little bits of the stator everywhere. The stator looks like it melted in a couple of spots along the outside edge. Is this normal? The inside of the flywheel was caked with crap from the stator too. Anyone have any ideas? PLEASE help!

 

[whiplash921]

Re: Merc 150 XR2 problem

Anyone Out There Have Any Ideas For My Problem? Please??!!

 

[andy6374]

Re: Merc 150 XR2 problem

Melted stator....gotta replace it. Replace with a CDI/Rapair stator as they are MUCH better than OEM.

 

[whiplash921]

Re: Merc 150 XR2 problem

I read somewhere that I should replace the rectifier when I replace the stator. I'm sure this is probably a good idea, but is it necessary? I know it's a lot cheaper than a lot of other parts on this motor, but should I just do it, or test it and see what I come up with? The other thing is that my tachometer has been acting weird since this problem first started. Are these two problem related? Thanks.

 

[whiplash921]

Re: Merc 150 XR2 problem

Alright. I put the new stator and rectifier on and the motor was PERFECT!!!! I put it on the water and I needed to adjust the idle a little, but other than that it was like brand new. I got on a plane, started to trim it out and was at about 57 MPH, my speedo might be a little low, and at 6K RPM. Got down about 1/2 mile and everything started to die. It died a little, came back, died a little more, I eased up on the throttle and it came off the plane and stalled. The only way I could get it started was by throttling it a little but once I put it in neutral, it died. I pulled the wires off and was getting no fire to cyls. 2, 4, & 6. My first thought was switch box, so I changed it with a spare, no difference. Then I thought maybe the stator failed already. I pulled the blue and red leads off of the switch boxes and ohmed it out. Between the red and blue going to the box going to 2, 4 and 6, it wasn't even close to spec. So just to be sure, I swapped the leads on the switch boxes and the symptom followed the leads. Bad stator out of box.... Unless anyone can think of something that could kill my stator, that is what I am assuming. My tach was working perfectly, I don't know where to go from here. I am going to order another stator and go from there. Any one have any ideas??? By the way, it was a CDI stator...

 

[j_martin]

Re: Merc 150 XR2 problem

Test the rectifier. There's a sticky on the forum that tells you how to do it with an ohmmeter. They're either good or bad, usually not intermittent.

Sometimes new parts fail, usually pretty quickly. It's just part of life.

John

 

[whiplash921]

Re: Merc 150 XR2 problem

Alright, thanks John. I'm not going to be able to test this until next week, but at least I know what to look for. I replaced my old rectifier with this new one without testing the old one, so I will test them both. By the way, the 2 yellow leads coming from the stator, they aren't marked any differently, so I assume that it doesn't matter where you put them on the rectifier, obviously except on the battery wire. Is this correct?

 

[whiplash921]

Re: Merc 150 XR2 problem

Is it at all possible that a bad switch box can kill a stator this fast?

 

[whiplash921]

Re: Merc 150 XR2 problem

I'm at the end of my rope. I can't figure this out. I replaced the stator again, and the motor didn't sound or feel right from the start. The timing was hard to check because it kept jumping around. I threw the muffs on, and it started, but just didn't seem right. I took it out on the lake anyways and it ran like chit. It took me so long to get on a plane it was disgusting. once I did, the motor felt like it was dragging everyonce and a while. My top speed without the motor trimmed up was about 40. The stator is new, one of the switchboxes is new, oh yeah, the new stator is fried again. 2nd one. Anyone have suggestions?

 

[whiplash921]

Re: Merc 150 XR2 problem

Well, 4 years in the making, I finally have my motor back. After troubleshooting and NOT throwing more money at this, I did some serious digging. The last time I ran this motor, I noticed that the flywheel was wobbling a fair amount. My first thought, bad crank bearing making the shaft wobble, making the flywheel wobble, smacking into the side of the stator, killing the stator. Well, I was mostly right. The crankshaft was bent. All of my time and effort for a bent crankshaft and now a completely rebuilt motor. I'm sure I could have got another motor for less money, but I love this motor. So, I'm breaking the motor in according to Mercury's specs and am on hour 8 and was on my way back to the dock and the motor came out of gear. Tried everything, it wouldn't go. In gear, the prop is locked like it's in gear. Out of gear, it spins freely. No reverse either. Weird stuff. Anyone have any thoughts? Thanks!