2005 Moomba Mobius Engine Hesitation

jaredhanson 09-23-2005, 1:48 PM

This boat has 34 hours on it and has been through the 20 hour service. The engine is carbureted. It was running fine until the last trip. It isn't idling well and hesitates when accelerating. There is also much more exhaust than normal, and it uses more fuel. Any ideas what I should check? The shop cannot look at it for two weeks. Thanks!

(professor) · (professor) **Join Date: Mar 2005** 09-25-2005, 6:27 PM

Jared:

I was having a similar problem with my Supra this summer. It turned out my perfect pass cable was getting hung up and causing rough idling and essentially no acceleration. I don't know if you have perfect pass, but it sounds like my situation and this simple step solved my problem. If you do have PP, look for the servo motor in the front of your engine box and follow that cable that is running into the engine. Make sure it is not getting hung up anywhere. I had to take the black plastic cover off my engine b/c the cable was getting hung up there. Just a suggestion you might want to try. Good luck!

Andy

(joesell) · (joesell) **Join Date: Apr 2001** 09-25-2005, 6:48 PM

I also had to modify my cover so the cable wouldn't get hung up. It's no big deal, it only took a few minutes to cut a notch in it so the cable could clear.

(greenthumb) · (greenthumb) **Join Date: Mar 2004** 09-25-2005, 6:55 PM

We have a 99 Moomba and find that ours hesitates when starting very quickly out of the hole.......only when we use regular gas. When we step it up to the supreme gas, the hesitation goes away within the first few hours.

(eustace) · (eustace) **Join Date: Nov 2002** 09-26-2005, 6:01 AM

The Indmar 310HP motor with the throttle body carb / injector should have a throttle position sensor. This may be causing the problem; you could try and remove it and clean it with contact cleaner or just try and replace it. The part is about $20 for a auto application, not sure if there is any difference in the marine version.

(eustace) · (eustace) **Join Date: Nov 2002** 09-26-2005, 11:06 AM

Jared, here is some information: http://autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/04/f8/d2/0900823d8004f8d2.jsp

jaredhanson 09-26-2005, 6:56 PM

Thanks for all of the suggestions! I checked it out this weekend and found a wire that was disconnected from the side of the carb. I connected it, and it ran fine. I then disconnected it and it still ran fine (maybe because I didn't let it fully warm up. Took it out to the lake Sunday and everything seems to be normal. Does anyone know what this wire is for? The + terminal was disconnected and the ground was in place. Choke, throttle position sensor, etc?

(acurtis_ttu) · (acurtis_ttu) **Join Date: May 2004** 09-26-2005, 9:12 PM

sounds like electronic choke wire?

(oulaxster25) · (oulaxster25) **Join Date: Feb 2004** 09-29-2005, 7:58 AM

We had a problem with our '04 supra not wanting to go out of the hole. We took it in and the first time they found that there was an oil leak, they fixed it all up. When we went out the next time the same thing, so we pulled the boat and took it back to the dealer and they found that we had a bad fuel pump. That was replaced and has been fine since.