stale gas
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=51357
Printed Date: January-15-2025 at 12:58pm
Topic: stale gas
Posted By: nobrainsd
Subject: stale gas
Date Posted: September-03-2023 at 4:43pm
|
A combination of events led to my boat sitting for 6 months. Never did that before. I run Stabil in my generators, but did not use in the boat. Won't do that again. Yep, it was an ethanol blend in the tank. Hard to get anything else here in CA. I had some issues with my carb (needle valves stuck closed). Cleaned it and started the engine. Oh my! I have heard knocking before, but nothing like that. Sounded like mechanical banging. Expected valve damage. Pulled exhaust manifolds, plugs and valve covers. Turned over engine by hand. Couldn't see anything amiss. Disconnected the distributor. Cranked the engine. Looked and sounded fine. Used a scope and viewed inside cylinders. No obvious issues and no debris. Guessing my fuel has way low octane remaining. Fn ethanol mix fuel! So I have drained the tank. Pulled it and got all of the fuel out. Plan to drain fuel lines, fuel water separator and fuel pump. Drain and clean carb bowls and passages. Fill with new gas and see what happens. The question is, do I need to go crazy cleaning the gas tank? As in use an industrial degreaser and power spray what I can? I'm not seeing or feeling any coating or varnish on the accessible tank surfaces. I would be stoked to hear what anyone else who has had stale gas has to say. I have it all apart so it would be good to do what I need to do :) Hmm, will find my compression gauge and check the cylinders today. Seems like a good idea.
|
Replies:
Posted By: KENO
Date Posted: September-03-2023 at 7:34pm
|
No comment on whether I think your problem is related to 6 month old gas with some percentage of ethanol in it, but there's that old saying............"dilution is the solution" You see and feel nothing out of the ordinary, in the tank so why put in some other chemicals and water with a power sprayer and then have to flush that stuff out? Fill 'er up, start 'er up and see what it sounds like if your compression check.is good  And rev it a little to ne sure it's not your damper plate with a big rattle.
|
Posted By: MrMcD
Date Posted: September-04-2023 at 1:35am
|
With only 6 mos sitting the fuel should have been OK, longer than that it gets iffy. The main issue running on old gasoline is it turns to a varnish like substance, when burned it will shellac the Valves and Piston Heads with a clear sticky substance that can make the valves stick in the head and hangs them open. Things go south from there. When removed the pistons are usually pretty with the clear varnish coating on the piston heads. The tell tell sign is the engine will STINK, it makes an odd smell that you will not forget if you run into it again. It is not a terrible smell just unique. If you are in a shop and one of these engines comes in the whole staff knows exactly what the problem is without looking by the smell. I had to clean out a tank with old gas in it a couple years ago, couple years old gas not 6 mos, I only had so many containers to hold it, I had to pull 40 gallons. When the tank still had a few gallons left I dumped the last 3 gallons into two of my own cars. Both are fuel injected engines, one was a 2003 Yukon the other was a 2012 GMC. Just the gallon and a half in each caused the engine to run rough and I had check engine lights popping on till that tank was burned up. Did no damage but I had to put up with lousy running engines for a while. My boat sits 6 mos without use almost every year and I do not worry about it. No problems in a FI GT40 so far. I do try and park it for the winter with premium fuel in there because I figure if it degrades it might still be OK to run but some years I forget and park with regular fuel in there. ------------- |
Posted By: 63 Skier
Date Posted: September-04-2023 at 9:38am
|
I run Stabil 360 in all my boat/tractor/small engine gas. Even if I know I'm going to burn through it. Gives me peace of mind, costs almost nothing. I agree that 6 month old gas shouldn't have caused the problems you were hearing, have a feeling you have something else going on, maybe the problem Ken mentioned. I would just add new gas and go from there.
------------- '63 American Skier - '98 Sport Nautique |