Mercury 1500 (in line 6, 150HP) issue with speed in foward

[rcornish]

Hopefully this is a simple question. I got this boat new to me this year. First time out, everything ran through the paces just fine without any problems. Got up into a plane just fine and would run faster than I really felt comfortable taking it too.

Fast forward to this weekend. Took it out and when I went to take off across the lake, the engine would only go up just a little past the idle speed, not near enough to get into a plane or anything. I was kind of surprised, as I had done nothing odd or anything in between the two outing that I am aware of. Just to check things, at some point I put in reverse and I still have a full acceleration there. When I got home, I had someone work the controls and and I can see a full moving on the throttle linkage and spark advance stuff when putting in full reverse, but it only starts to move that way when in full forward. My question: Is this just the cable needs to be adjusted or is more likely something is broken somewhere?

A second question: I would like to get hold of some manuals for it, but I can't seem to find the serial number/model number. Where should I be looking for them? If it makes a difference it has a trim package on it.

Thanks in advance,
Ray

 

[Chris1956]

Re: Mercury 1500 (in line 6, 150HP) issue with speed in foward

Ray, the issue is hard to judge from your description. If you put the motor in forward and push the throttle all the way, the throttle plates (AKA Butterflies) should be nearly full open. If not, you have an issue in the linkage or cable.

That motor should have a distributor. If not, you have a Frankin-Merc. You might post serial number so we can identify

 

[rcornish]

Re: Mercury 1500 (in line 6, 150HP) issue with speed in foward

Ray, the issue is hard to judge from your description. If you put the motor in forward and push the throttle all the way, the throttle plates (AKA Butterflies) should be nearly full open. If not, you have an issue in the linkage or cable.

That motor should have a distributor. If not, you have a Frankin-Merc. You might post serial number so we can identify

I will try to look and see what the throttle plates are doing this evening to answer that part. Also, the 2nd part of my question above was where do I even find the serial number. I was looking for it, because I figured anyone on here would want that, but I could not find it. It is a distributor system though, unless electronic ignition looks like a distributor <grin>.

 

[Chris1956]

Re: Mercury 1500 (in line 6, 150HP) issue with speed in foward

serial number should be on transom clamp. Backup plan is to look for serial number on he plug on the powerhead. Third plan is to look for part number on starboard side of block, about halfway up.

 

[rcornish]

Re: Mercury 1500 (in line 6, 150HP) issue with speed in foward

Serial number is 4754153. That makes it a 1977 model based on my quick looking it up.

I checked and when pushing the controller for forward acceleration, it is barely moving any of the linkage. This includes the butterfly throttle plates. Really, looks like they are NOT opening at all. As stated before, when I put in reverse and push to be wide open it is indeed, including the butterfly plates. It is almost like something has come loose in the control box, is that a possibility?

Thanks again ahead of time for the assistance on this.
Ray