Author Topic: Excessive fuel smell & gas used - 2 stroke. ** Possible Culprit Found **  (Read 3766 times)

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Online AJFishin

I'm out running my boat for the first time today. While out cruising around I've notice a strong fuel smell and excessive amount of gas being used.

I pulled into a marina and had a guy that knows a little about 2-stroke engines check it out. He noticed the little red switch on the carb was turned in the wrong direction. He adjusted it but I still get the fuel smell, although not as constant, maybe because of the wind, but still smell fuel.

Does anyone know what it might be or point me in a direction of a solution?

Thank you
« Last Edit: July 13, 2015, 06:01:26 PM by AJFishin »
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline Croaker Stroker

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #1 on: July 12, 2015, 01:11:11 PM »
Two strokes always smell somewhat. Is the gas in your tank old ?

Mine smells because I add Stabil.  :shrug9:

A SeaFoam treatment might improve it.
« Last Edit: July 12, 2015, 01:14:16 PM by Croaker Stroker »
1987 - 17' Sea Pacer - 2004 Evinrude 90 E-tec
15' Sea Sprinter - **SOLD**

"If a fish will, he will… if he won't, he won't… and that's about it… except… he may take this when he won't take that."

Offline BayWolf

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #2 on: July 12, 2015, 02:18:56 PM »
How old are your fuel lines? Are they in good shape? Are they marine grade? Auto fuel line will allow vapor to seep through as they age. Brittle old lines will cracking and allow vapors and even fuel to seep.
"Forgiveness is between them and God. My job is to arrange the meeting."

First Sergeant
U.S. Army (retired) :flag:

Offline whale

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #3 on: July 12, 2015, 02:28:31 PM »
What is excessive?
How much fuel did you go through?
It's best that you give more info on your fuel system, from the tank to carb. What's new, what's not.
You didn't notice it when you run the motor at home?
2014 Sea Chaser 17, Yamaha F90, T9.9

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #4 on: July 12, 2015, 04:52:23 PM »
All new lines and new gas.
When I ran it at home, I didn't notice the fumes, but did noticed, what looked like gas/oil that came out of the prop after it was done running. I thought I flooded the system since it was the first time starting up in 2 years.
I guess I will have to go through each and every hose on the engine to see if there's one that is not tight on the fitting.

While heading back to the docks, 5 MPH, I noticed it bogged down for a couple seconds then returned. Then when I was at the clean out station,  to run freshwater through the engine,  it was a little harder to start and took a little more (choke) to turn over.

Questions on my mind.
Could it be a bad fuel pump?
Carbs out of sinc? ( i've rebuilt my carbs)
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Online headduck

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #5 on: July 12, 2015, 06:14:13 PM »
I fought my old Johnson for a while then relented and sold it...new owner said that there was a leaky fuel line to the carb...acted up most when under load and throttle...rarely a problem in  the driveway... :shrug9: but caused a bunch of issues ib the water...hard start, bogging, and basic unreliability...he sorted the misc leaks and it runs well for him...
1987 17' Sea Ranger 2015 Mercury 115 2012 Evinrude 9.8

Offline Sea Bear

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #6 on: July 12, 2015, 07:18:08 PM »
Are you smelling raw gas???

IMHO, you should never smell raw fuel on your boat.  If the you smell raw gas, you have a safety issue and you shouldn't run the boat until you find the leak and fix it.  Hopefully you are just smelling exhaust.
1981 Arima Sea Chaser 17'
Evinrude 70hp 2 stroke & Evinrude 9.5 Sportwin

www.skagitbroomworks.com

Offline Croaker Stroker

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #7 on: July 12, 2015, 08:25:01 PM »

I think you just need to run it. Sounds like gunky gas and goop in the fuel system.

1987 - 17' Sea Pacer - 2004 Evinrude 90 E-tec
15' Sea Sprinter - **SOLD**

"If a fish will, he will… if he won't, he won't… and that's about it… except… he may take this when he won't take that."

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #8 on: July 12, 2015, 08:46:04 PM »
Are you smelling raw gas???

IMHO, you should never smell raw fuel on your boat.  If the you smell raw gas, you have a safety issue and you shouldn't run the boat until you find the leak and fix it.  Hopefully you are just smelling exhaust.

It is raw gas, that's why we got off of the water shortly after.

Could the reason be that I had to go 5MPH  in the harbor and I kept the RPMs around 14 (gauge has only 2 digital read out, guessing 1400 RPMs) for a long time?
I also noticed it drank hell of a lot of gas at first, but after the guy turned the switch, it looks like I used less gas, but I'm not 100% sure.
« Last Edit: July 12, 2015, 09:02:08 PM by AJFishin »
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #9 on: July 12, 2015, 09:53:13 PM »
What is excessive?
How much fuel did you go through?
It's best that you give more info on your fuel system, from the tank to carb. What's new, what's not.
You didn't notice it when you run the motor at home?

What is excessive?
- The smell was bad enough that a sailboat that was passing me said he could smell it way behind me.

How much fuel did you go through?
- The first 30-40 mins went through about 4-5 gallons.:hoboy:  Went to the gas dock, talked w/ a guy who knew a little about 2 strokes, noticed the little red switch on the middle of the 3 carbs was set to emergency. :doh: He switched it to "normal" and heard the engine run, which he said it sounded really good. After that I stilled smelled fuel, but not as much.

fuel system, from the tank to carb. What's new, what's not.
- New: Hoses and filters.
- NOT new: Fuel pump.

You didn't notice it when you run the motor at home?
- What I noticed while the engine was running, for about 10 minutes from a 1 gallon fuel tank, the gas was sucked up quick. (probably because it was in the emergency position) Tilted the engine up, then an hour later brought engine down, noticed about a 1/4 of a cup worth of oil/gas poured out.

Engine running:

« Last Edit: July 13, 2015, 10:22:57 AM by AJFishin »
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline Croaker Stroker

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #10 on: July 12, 2015, 10:10:12 PM »
I think the lever is your "Enrichment lever"....sort of like an emergency choke when your engine wont start when it's cold. Running with it engaged would cause a bad gas smell.  Raw gas would be running out of your exhaust.

It's going to take a while to run out the goop.
« Last Edit: July 12, 2015, 10:13:26 PM by Croaker Stroker »
1987 - 17' Sea Pacer - 2004 Evinrude 90 E-tec
15' Sea Sprinter - **SOLD**

"If a fish will, he will… if he won't, he won't… and that's about it… except… he may take this when he won't take that."

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #11 on: July 12, 2015, 10:21:02 PM »
I think the lever is your "Enrichment lever"....sort of like an emergency choke when your engine wont start when it's cold. Running with it engaged would cause a bad gas smell.  Raw gas would be running out of your exhaust.

It's going to take a while to run out the goop.

"Enrichment lever" - I think that's what the guy called that red switch.

When you say "goop" what are you referring to? And would this be caused by the "Enrichment lever" being set to emergency?
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline Threeweight

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #12 on: July 12, 2015, 10:30:36 PM »
Couple thoughts... it may have just been the richness lever on the carb, but the fuel you describe that leaked when you titled the motor makes me think you might have something else going on.

Run the engine in a trash can filled with water in your driveway with the cowling off.  Look for any signs of leaking fuel.  What you describe could be caused by a sticking float or a bent float arm, which causes the carb fuel bowl to overfill then dump fuel overboard.  Given the fuel that leaked when you tilted the motor, this seems like a possibility.

Also, the enrichment lever being turned on may not be the only richness issue the motor has.  All my carbed motors have had air/fuel richness adjustment screws, the change how much of each the motor is getting.  You need a shop manual to know how to adjust this.  If it is set too rich you can get a strong fuel odor from the exhaust.

The oily goo coming out of your prop is normal for a carbed two stroke.  One of the joys of carbed motors the rely on their fuel for lubrication.
« Last Edit: July 12, 2015, 10:37:56 PM by Threeweight »
Former Sea Chaser 17 owner
Wild Card, Hewescraft Ocean Pro 220, Honda 225 and 9.9

“Never turn your back on fear. It should always be in front of you, like a thing that might have to be killed.”
       --- Hunter S. Thompson

Offline whale

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #13 on: July 12, 2015, 10:35:48 PM »
what is your oil consumption compared to your gas?
If it's off, it's before your mixing unit.

Leak can be anywhere. Hoses, flooding carb, crank case leak, too much fuel escaping to your exhaust...
Does it sounds like it been choked all the time?
2014 Sea Chaser 17, Yamaha F90, T9.9

Offline Croaker Stroker

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #14 on: July 12, 2015, 11:13:15 PM »
I think the lever is your "Enrichment lever"....sort of like an emergency choke when your engine wont start when it's cold. Running with it engaged would cause a bad gas smell.  Raw gas would be running out of your exhaust.

It's going to take a while to run out the goop.

"Enrichment lever" - I think that's what the guy called that red switch.

When you say "goop" what are you referring to? And would this be caused by the "Enrichment lever" being set to emergency?

Goop = Unburned gas/oil mixed with carbon build up from running with the Enrichment lever on. I wonder how long your motor has been run like that ? if you are on speaking terms with the previous owner, you might ask him about it.

Running a few tanks of clean gas should clean it all out.

Do a search for "SeaFoam".  This stuff will dislodge carbon and clean out your fuel system.  There are instructions on the "SeaFoam" website.  There are also threads on this forum on the subject of SeaFoam.
« Last Edit: July 12, 2015, 11:30:31 PM by Croaker Stroker »
1987 - 17' Sea Pacer - 2004 Evinrude 90 E-tec
15' Sea Sprinter - **SOLD**

"If a fish will, he will… if he won't, he won't… and that's about it… except… he may take this when he won't take that."

Offline Markshoreline

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #15 on: July 12, 2015, 11:33:49 PM »
You should also change spark plugs before running it again, the current ones could be fouled.
2002 Sea Ranger HT 21, Yamaha 150, Yamaha 9.9

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #16 on: July 13, 2015, 08:28:13 AM »
Couple thoughts... it may have just been the richness lever on the carb, but the fuel you describe that leaked when you titled the motor makes me think you might have something else going on.

Run the engine in a trash can filled with water in your driveway with the cowling off.  Look for any signs of leaking fuel.  What you describe could be caused by a sticking float or a bent float arm, which causes the carb fuel bowl to overfill then dump fuel overboard.  Given the fuel that leaked when you tilted the motor, this seems like a possibility.

Also, the enrichment lever being turned on may not be the only richness issue the motor has.  All my carbed motors have had air/fuel richness adjustment screws, the change how much of each the motor is getting.  You need a shop manual to know how to adjust this.  If it is set too rich you can get a strong fuel odor from the exhaust.

The oily goo coming out of your prop is normal for a carbed two stroke.  One of the joys of carbed motors the rely on their fuel for lubrication.

I think with the excess fuel from running it at home was just that, the richness level being set to emergency level, or that is what I hope.
I have a shop manual now so I'm going to look through that for the adjustments.
I'm going to run the engine in a trash can later today like you said and hopefully I will see where the gas is coming from.
Question, is there a way to "see", while the engine is running, if the float is stuck?  I've purchased a complete carb rebuild kit that I should get by Friday, hopefully sooner. Might as well start with a complete rebuild.

To answer a question regarding the oil level. The oil in the reservoir was topped off and the amount of oil used, if measured from top down, was about 1" or so.
I put exactly 15 gallons of gas in the tank, the tank was empty, and used roughly about 7-8 gallons of gas total for the day. But remind you, the enrichment level was set on emergency for the first 30-40 minutes of running. At that time I never went over 8MPH because of speed restrictions in the harbor. I estimate I used about 5 gallons of gas in that time. I can double check the total amount used, for both, when I get home later.
« Last Edit: July 13, 2015, 10:31:12 AM by AJFishin »
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline blindmonkey

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #17 on: July 13, 2015, 08:36:38 AM »
You should be able to check for any fuel leaks by pumping the primer bulb hard and watching. If the bulb starts losing pressure it's either an air leak or fuel leak.
Lorne
2013 17' Sea Chaser, Honda 90, Yamaha F8
1994 Sea Explorer, Mercury 60, SOLD

Offline Sea Bear

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #18 on: July 13, 2015, 09:15:43 AM »
It sounds like you have a stuck float in one of your carbs.  When is the last time the carbs were removed, disassembled and cleaned?  A stuck float will give you a lot of raw gas out the exhaust.
1981 Arima Sea Chaser 17'
Evinrude 70hp 2 stroke & Evinrude 9.5 Sportwin

www.skagitbroomworks.com

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #19 on: July 13, 2015, 09:50:56 AM »
It sounds like you have a stuck float in one of your carbs.  When is the last time the carbs were removed, disassembled and cleaned?  A stuck float will give you a lot of raw gas out the exhaust.

About 2 weeks ago I removed the carbs and cleaned them. i just bought a new rebuild kit that I should get by Friday, but not sure if this will be the fix. So I'm still trying to see what other possibilities it could be.

Thanks
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #20 on: July 13, 2015, 10:55:50 AM »
I just wanted to give some visuals here.
Here's a picture of my oil reservoir. Before heading out, I filled it up to the top, on the right side. This is how much was used

Oil Reservoir:


Fuel Tank:
« Last Edit: July 13, 2015, 11:04:31 AM by AJFishin »
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline Threeweight

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #21 on: July 13, 2015, 11:04:24 AM »
If the motor uses oil at a 50:1 ratio, then for 15 gallons of fuel you would have used about 40 ounces of oil (or about 1/3 of a gallon).  More if the engine runs at a 40:1 or 30:1 ratio.

How much oil does the reservoir hold?

Former Sea Chaser 17 owner
Wild Card, Hewescraft Ocean Pro 220, Honda 225 and 9.9

“Never turn your back on fear. It should always be in front of you, like a thing that might have to be killed.”
       --- Hunter S. Thompson

Offline Croaker Stroker

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #22 on: July 13, 2015, 11:04:32 AM »
I also use about that much oil when I burn 7 to 8 gallons of gas. (50:1)
1987 - 17' Sea Pacer - 2004 Evinrude 90 E-tec
15' Sea Sprinter - **SOLD**

"If a fish will, he will… if he won't, he won't… and that's about it… except… he may take this when he won't take that."

Online AJFishin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #23 on: July 13, 2015, 11:14:52 AM »
If the motor uses oil at a 50:1 ratio, then for 15 gallons of fuel you would have used about 40 ounces of oil (or about 1/3 of a gallon).  More if the engine runs at a 40:1 or 30:1 ratio.

How much oil does the reservoir hold?

How much oil does the reservoir hold?
- 3.0 quarts (2.8 L)

So what I'm thinking here, is I'm more or less I'm under that calculation by the way it looks in my oil tank, since it was not filled up completly.  So lets say at 6.5 gallons of gas used, I should have used a little more than 1/2 of quart of oil, correct?
Reason for not using the correct amount of oil would be due to the enrichment switch set to "emergency", thus pumping more gas than oil?
I just trying to figure things out here aloud.
« Last Edit: July 13, 2015, 11:45:09 AM by AJFishin »
'96 Sea Chaser 1511 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline Threeweight

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #24 on: July 13, 2015, 11:39:55 AM »
For 7 gallons gas consumed, that seems about right.  Looks like your oiling system is working fine.  Whatever is happening is happening after the oil mixer, IMO.
Former Sea Chaser 17 owner
Wild Card, Hewescraft Ocean Pro 220, Honda 225 and 9.9

“Never turn your back on fear. It should always be in front of you, like a thing that might have to be killed.”
       --- Hunter S. Thompson