Could bad gas cause poor idling?

[fourtwenty]

Towards the end of last fall I bought a boat for which I had been asking questions about in this thread:

2001 bayliner 175BE what to look for after sitting 4 years?

This week I am going to look at a 2001 Bayliner 175BE. The owner says its was winterized 4 years ago and it has been stored in shrink wrap in a garage since. If it looks ok I would have a marine mechanic check it over fully before buying but I was wondering if there are obvious signs of problems...

forums.iboats.com

2001 Bayliner 175BE
3.0L Mercruiser
Alpha One Gen II

It got too cold for me to start it up myself last fall but it did start when I had the shop look at it. Their report was that it idled a little low when in gear but otherwise ran ok.

Today I fired it up (on muffs) and it won't stay running in the neutral position. Seems to run real nice with the throttle up a bit. Unfortunately the tach doesn't work so I have no idea what sort of RPM it's doing. When I bump it back to neutral it just dies.

My question is, could old gas be causing this problem? The gas is 4 years old, and had stabilizer added when it was last winterized. The gauge shows less than 1/8 tank so I was going to go fill up a few jerry cans, add new fuel and see what happens.

Right now it's 9C (48F) outside, could cold be another reason?

It's going to the shop next week to get all the bellows replaced and i will get them to have a look at the motor too but it would be nice to eliminate a few things first.

 

[alldodge]

Could bad gas cause poor idling?​

Yes

Gas being 4 years old, I would drain it. Adding good gas to bad can make more bad gas

Pull the fuel filter and drain it into a clear container. It should be clear, smell like gas and not rotten.

 

[dingbat]

Right now it's 9C (48F) outside, could cold be another reason?

How does you car start and run at 9C?
No reason your boat shouldn’t start and run the same.
Fresh fuel and probably a carb cleaning

 

[kenny nunez]

Try this. Gently screw in the idle metering screws and count the turns, remove them then shoot some carburetor spray into the holes followed by compressed air if you have a compressor if not then shoot some more spray into the holes, re-install the screws at the count to remove them. Usually they are 1.5 turns from seated.
Good luck

 

[crazy charlie]

Old fuel can certainly cause the issue you describe.However it sounds like you kinda had the low idle issue beforehand,now it is a little worse.Here is what ALWAYS has worked for me.First empty your fuel water separator into a jar (tall and thin is best) and put aside for later inspection.Fill separator with 3/4 fresh gas and 1/4 Seafoam and reinstall..Add to fuel tank a few gallons of fresh fuel,the balance of can of Seafoam and a can of Chemtool.Now run the motor and keep idle where it needs to be so no stall.Gonna be smokin so dont panic.Let it run through as long as you can .Without too much movement,Take a look at the old fuel to see if there are a few layers.top layer may be water.This will be a decent indicator of what was in the tank.When you ran most of the concoction through ,see if it idles better.Either way change out the seperator to new and pull plugs and clean them or change them.There should be an improvement but as previously stated the idle has been low from the start.Tweak up idle screw a tad .Post back whats going on.Good luck!! Charlie