Trouble at idle speed

[Xelaw]

I just bought a 2007 Four Winns Horizon 180 with a 190HP 4.3L Mercuiser. The boat runs well, except I've noticed some problems while idling. Not sure if both are related. Let me know what you think.

1) Motor runs fine while throttle is open, but stalls during idling. I have to rev the throttle a bit then pull it back to restart the motor if it stalls out. This boat had gas that sat for about a year, but I've gone through two tanks of good gas since buying it. The problem seems to be getting better with each time I run the boat, so maybe it was just a problem with old gas. I've run it about 6 times total. What else should I look at to fix this?

2) I have to open the throttle pretty hard to get the boat to start moving forward from idle. If I push the throttle from idle speed slowly forward, it stalls out. It would be nice to move a little faster in a no wake zone but if I try to idle faster it stalls every time. I had this issue with my old boat too, so I wasn't sure if it's normal.

Any advice would be appreciated.

 

[Bondo]

Re: Trouble at idle speed

Ayuh,... My guess is, the carb still has crap in it from the old gas...
Rebuilding the carb might help...

 

[Xelaw]

Re: Trouble at idle speed

Sorry, I should have stated that the motor uses EFI. I ran fuel injector cleaner through it once, I may try it again and go through a couple more tanks before taking a closer look at the injectors. Should I put high octane gas in it? I've heard that you aren't supposed to do that for boat motors, but a few people have suggested it.

Also, does it seem like my two problems are related?

 

[Bondo]

Re: Trouble at idle speed

Should I put high octane gas in it?

Ayuh,... Other than lightening your Wallet, it won't help... Pretty much a Waste of money...

 

[Xelaw]

Re: Trouble at idle speed

So running a couple tanks of high octane won't help clean the injectors? Does the additive stuff work well or do I need to clean them manually?

 

[Xelaw]

Re: Trouble at idle speed

I put 92 octane in and both of the problems didn't occur this weekend. I'm going to keep using higher octane gas the next few times I take it out, then switch back to regular. According to Mercury, 92 octane is acceptable: http://www.mercurymarine.com/servic...nd-maintenance/faqs/mercruiser/?category=fuel

 

[Aloysius]

Re: Trouble at idle speed

Octane rating and fuel detergents are totally unrelated. If you notice a difference, it is probably because the premium has less alcohol in it. Or..the 87 octane had too much alcohol.

I don't know where 92 octane is sold, but some gasolines are regionalized by adding components that enhance performance in cold weather.

 

[sethjon]

Re: Trouble at idle speed

So running a couple tanks of high octane won't help clean the injectors? Does the additive stuff work well or do I need to clean them manually?

Depends on how bad they are but the motor isn't that old. Sounds like a bad conncetion. check the plug wires first. Have you tuned it since having the problem?

 

[Xelaw]

Re: Trouble at idle speed

I've taken it out quite a few times since my last post and it runs great now. It was definitely due to bad gas. I put STA-BIL in every time I fill it now.