Author Topic: Excessive fuel smell & gas used - 2 stroke. ** Possible Culprit Found **  (Read 4077 times)

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Offline AJFishin

Re: Excessive fuel smell & gas used - 2 stroke. **Update w/ video**
« Reply #25 on: July 13, 2015, 05:55:33 PM »
Possible culprit found!!

Well I ran the engine and with a few seconds I believe I found where the gas is coming from. It seems to be coming from the bottom carburetor, pouring out. I didn't see any fuel lines leaking, doesn't seem to be any lines disconnected. But I saw the gas coming out of the hole on the carb.

See video.

Questions now:
Why is it coming out from this hole?
How to fix it?



After removing the engine out of the can, I raised up the engine for about 10 minutes. When i came back and set the engine down I noticed oil/gas mixture pouring out down and over the skeg. Is this because of the fuel coming out of the carb with the engine was put up, thus allowing the fuel to run down and out over the skeg?


« Last Edit: July 13, 2015, 06:59:12 PM by AJFishin »
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Online Hydroman

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #26 on: July 13, 2015, 06:00:29 PM »
Most like the float needle is not seating properly or needle valve I level is set too high and the hole is flowing out of the over flow hole'
17 Sea Chaser (sold)
21 Skip Tower (sold)
27 Thunder Jet OS

Online First Cabin

Re: Excessive fuel smell & gas used - 2 stroke.
« Reply #27 on: July 13, 2015, 06:10:15 PM »
Most like the float needle is not seating properly or needle valve I level is set too high and the hole is flowing out of the over flow hole'


I agree.

Definitely need to rebuild those carbs!
First:  1982 15' SeaHunter, Yamaha 70 2-stroke, Yamaha F6
Second:  1987 17' SeaRanger, Merc 90 2-stroke, Yamaha F8
Current:  2002 17' SeaChaser, Yamaha F100, Yamaha T8

Online Hydroman

Not sure is float is solid  or actually a real float and hollow.  If hollow it may have hole in it is full of fuel.

Jim
17 Sea Chaser (sold)
21 Skip Tower (sold)
27 Thunder Jet OS

Offline AJFishin

Most like the float needle is not seating properly or needle valve I level is set too high and the hole is flowing out of the over flow hole'


I agree.

Definitely need to rebuild those carbs!


I've ordered the rebuild kit for all 3 carbs that should be here by Friday.

Not sure is float is solid  or actually a real float and hollow.  If hollow it may have hole in it is full of fuel.

Jim

Last time I had the carbs apart I believe they were hollow. I don't recall seeing any holes or fuel in them, but, tomorrow I will be checking them to make sure.

Thanks
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline whale

Didn't you change the float last time?
Old gas does become varnish that sticks to everything, weighing the float. You have to scrape everything off.
Check the valve seat, make sure it's not varnish blocking it.
2014 Sea Chaser 17, Yamaha F90, T9.9

Offline Threeweight

If the floats are hollow, it is also possible one spring a leak and doesn't float any more.

The purpose of the floats is to keep an adequate fuel supply in the bowl of the carbs, but to meter or shut it off if the engine isn't burning that much.  If it sticks the fuel just keeps pouring in even if the engine can't burn it.
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 AJFishin

Didn't you change the float last time?
Old gas does become varnish that sticks to everything, weighing the float. You have to scrape everything off.
Check the valve seat, make sure it's not varnish blocking it.

The floats were not changed out, but cleaned up.
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline AJFishin

If the floats are hollow, it is also possible one spring a leak and doesn't float any more.

The purpose of the floats is to keep an adequate fuel supply in the bowl of the carbs, but to meter or shut it off if the engine isn't burning that much.  If it sticks the fuel just keeps pouring in even if the engine can't burn it.

Going to pull the carbs tomorrow and see what's going on there. Hopefully this will answer some questions.

Thanks
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline AJFishin

I'm glad I've pulled the carbs off a few times, because it makes pulling them off again a lot easier and faster, haha.
After pulling the carbs off and rebuilding them I think I got the gas leak fixed. Turned the engine over and ran it for a few minutes and I didn't see or smell any gas. This weekend I'm going to do another water trial, but that depends if this predicted thunderstorm actually rolls in.

Hope all will be good so we can start enjoying!

Thank you to everyone that helped me on narrowing it down. I just hope that's it!

Here's the engine running:
« Last Edit: July 17, 2015, 09:06:27 PM by AJFishin »
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline AP

Nice work!  It is always cool to see someone dive into a problem and work through it.  It sounds like you not only improved your situation but you've become much more familiar with the motor.   The pics and vids you posted were a great.

Offline AJFishin

Nice work!  It is always cool to see someone dive into a problem and work through it.  It sounds like you not only improved your situation but you've become much more familiar with the motor.   The pics and vids you posted were a great.

Thanks. I'm glad it's a smaller size engine which helps out on the learning curve.
Just like others, I hope the pictures and videos will help someone else out in the future if they happen to have a similar issue. Just makes things easier.
This site is great with tons of information and helpful people. With everyone that helps out, it makes learning and understanding boating issues easy enough for you to know it's possible to do the work yourself.
« Last Edit: July 18, 2015, 02:33:39 PM by AJFishin »
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !

Offline Sea Bear

Glad you figured it out!  It seems the bottom carbs collect all the crud and get problems first.  My guess is the float is o.k. but the float valve is dirty and not seating.  Probably gummy 2 stroke crud down there.  Easy fix.  :applause:
1981 Arima Sea Chaser 17'
Evinrude 70hp 2 stroke & Evinrude 9.5 Sportwin

www.skagitbroomworks.com

Offline AJFishin

Glad you figured it out!  It seems the bottom carbs collect all the crud and get problems first.  My guess is the float is o.k. but the float valve is dirty and not seating.  Probably gummy 2 stroke crud down there.  Easy fix.  :applause:

Yea I think that's exactly what it was and the rebuild looks to have hopefully fixed it.
Unfortunately due to the crazy thunderstorms we had this weekend, I wasn't able to put the boat in the water.


But next weekend looks great, can't wait! :gone_fishing:
« Last Edit: July 20, 2015, 09:57:37 PM by AJFishin »
'96 Sea Chaser 16 - Yamaha 70HP - 2 smoke

! Go Kings Go !