Altitude Problems

(jcurtis) · (jcurtis) **Join Date: Mar 2007** 07-09-2007, 10:54 AM

I have a 99 Maristar with the 330 hp motor. I just got back from a week in Tahoe (elevation 6200 ft) The boat would not idle well and would load up a bit, once I got it going above 1500 rpm or so, it ran fine. I changed the plugs, put a smaller prop on and still same problem. I got it home last night, started it in the driveway with the fake lake and it ran fine. Any suggestions of what it may be? I had a mobile mechanic come to our pier and look at it, he told me it may be the fuel pump, but since it ran fine at sea level, I am a little skeptic...

(rallyart) · (rallyart) **Join Date: Nov 2006** 07-10-2007, 12:49 AM

Its too rich @ idle at altitude. Adjust the idle screws if it is carbed.

(jcurtis) · (jcurtis) **Join Date: Mar 2007** 07-10-2007, 8:29 AM

it is fuel injected, that is why I am so perplexed by the situation...

(dhcomp) · (dhcomp) **Join Date: Jun 2003** 07-10-2007, 8:45 PM

I dont' know about the idle, but u definitely need to drop down about 2+ " in prop pitch to regain your holsehot.