2001 150 HP Saltwater Series V6

[jasonbailey]

My brother just bought a 2001 206 Proline Walk around cuddy cabin with a 150HP Merc Saltwater series O/B. At WOT the boat is maybe doing about 25 MPH and turning about 3500 RPMS. I come from the Chrysler/Force world, and my old Chrysler at WOT will turn about 5200. I would expect a boat of that size and o/b combo should run 40 to 45 MPH at WOT.<br /><br /> I do not think he is over propped. We did a compression check tonight, about 115 on all 6 cylinders. The spark plugs were black and oily they were NGK's and appeared to be the original set. At higher idle it did not appear to have a miss, but it idles kind of rough. We are going to put a new set of plugs in tomorrow and dump two cans of Sea Foam in the gas tank.<br /><br /> He has decided to keep it in the water and the hull is already covered in all sorts of interesting marine life. The bottom has been painted, but it was not painted this year. We are going to pull it out this weekend and pressure wash all the junk off the hull. I suspect that is slowing it down as well.

 

[wilde1j]

Re: 2001 150 HP Saltwater Series V6

Your motor should be turning ~ 5500 RPM @ WOT. Growth on the bottom will slow the boat, but shouldn't have a major impact on engine RPM. I would suspect a fuel delivery problem (i.e. air leak on the pump suction side, restriction, fuel pump problem, tank not vented properly, etc.)

 

[jasonbailey]

Re: 2001 150 HP Saltwater Series V6

I was just thinking about a fuel pump diaphram. The tank is in the hull, a 70 gallon tank. I'll make sure that the tank is vented properly. With a hull tank is there a vent screw/opening? My tanks are the 12 gallon variety that sit in the back of the boat that you open manually so I'm not all that familer with the hull tank. <br /><br />Does this motor have a convential diaphram that I would be used to on a carberated motor? I just want to help him get pointed in the right direction so he does not fork over a bunch of money on needless repairs. I'm super lucky, my old Chrysler is very easy to work on. And yes, I use it more than I work on it....

 

[wilde1j]

Re: 2001 150 HP Saltwater Series V6

With in hull tank, the vent is plumbed to a vent fitting typically on the side or stern of the hull. Make sure the hose is properly routed and not kinked.<br /><br />There's another thing to check at the tank ... sometimes an anti-syphon valve in the tank outlet will hang up, preventing full fuel flow.<br /><br />Is the motor an EFI or carbed type?

 

[jasonbailey]

Re: 2001 150 HP Saltwater Series V6

Motor is EFI.

 

[Coolmaker]

Re: 2001 150 HP Saltwater Series V6

The hull growth will certainly keep the motor from turning the proper RPM's. Clean the hull first before doing any major repairs...

 

[wilde1j]

Re: 2001 150 HP Saltwater Series V6

Try here for more troubleshooting info, especially for the EFI:<br /><br /> http://www.biggerhammer.net/mercury/factory_manuals/Service_Manual_Index.html <br /><br />Good luck!