2003 75 hp Merc Rough Idle

[Daymskipy]

I have a 2003 Mercury 75hp that I bought last year @ Bass Pro on a Tracker Grizzley Boat. Went through the burn in that was given by Bass Pro and I have had a severly rough Idle since. I have changed the plugs thinking that I possibly fouled them and that has not fixed the problem. The motor seems to be very hard to start as well. Have to choke it 10 times prime the bulb hard and then raise the warm up lever to the top and then crank while choking to get it to start after 20 seconds or so. This sure is freaking me out. The motor seems to be running so erraticly that the whole back end of the boat shakes when it does start to idle. Mind you that I have the warm up lever back down to the idle position here.... Any suggestions?

 

[achris]

Re: 2003 75 hp Merc Rough Idle

Have you taken the engine back for the 20 hour service yet? If not, take it back for the service and tell them about the poor idle. It'll probably be a mixture adjustment. <br /><br />Chris.............

 

[Daymskipy]

Re: 2003 75 hp Merc Rough Idle

Chris, <br /><br /> I have not taken it in for the 20 hr yet because I have not gotten near 20 hours (unfortunately). I am sitting about 11 hrs thus far. I will try the 20 hr service and see where that puts me. Does anyone know an approximate price range for this service? Thanks <br /><br />Mike

 

[WillyBWright]

Re: 2003 75 hp Merc Rough Idle

I don't want to stick my foot in my mouth here, but do those guys service what they sell or do they just sell? If they just sell, then that motor was taken out of the box and hung on the boat and never fine tuned. They ballpark settings at the factory, but they need some additional tweaking depending on conditions where you're at which is probably different than conditions at the factory. I'm lucky. I live near the factory, so they're usually pretty close around here. But they still need a bit of attention now and then.<br /><br />I should add that those motors do idle worse than just about any motor out there. The only one I can think of that idles worse is a 90 Merc. I should also add that I'm assuming you have a two-stroke. Four-stroke 75s idle very nicely indeed!