Gas in Crankcase

C

Crankcase

Recruit
Joined
Jun 6, 2005
Messages
4
Why does gas enter the crankcase and dilute the oil? This problem is worst in the winter. I have a 2000 15hp Honda 4-stroke outboard motor.<br />Bill<br /><br />I am asking the above question on behalf of a no computer friend who has been struggling with this for some time. Thanks for any help.<br />Marcia (no motor friend :)
 
A

AG

Seaman Apprentice
Joined
Jun 12, 2004
Messages
36
Re: Gas in Crankcase

I read somewhere that the reason is that the air vent on the gas tank is closed. When that happens the sun heats up the tank and the gas comes right into the crancase. There are far more knowledeable guys on this board than I, it's one theory.
 
JB

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Gas in Crankcase

Look at Engine FAQs, Marcia.<br /><br />Good luck. :)
 
C

Crankcase

Recruit
Joined
Jun 6, 2005
Messages
4
Re: Gas in Crankcase

Hi AG Thanks for the suggestion. I'll pass this on to my friend and hope that it helps. I guided him through the engine faq's before posting but he couldn't find the answer he was looking for and with no knowlege of motors, it is difficult for me to know what to look for myself. <br />Thanks again<br />Marcia
 
C

Crankcase

Recruit
Joined
Jun 6, 2005
Messages
4
Re: Gas in Crankcase

Hi Z-Man<br />Thanks for the link which I just checked out. It's the same one that I had highlighted and showed him before posting. For some reason he dismissed it so will have to show it to him again and find out why. I know nothing about these things but was able to navigate him to this site and that answer. Maybe I should take up boating. :) Thanks for your help.<br />Marcia
 
ziemann

ziemann

Chief Petty Officer
Joined
Apr 28, 2004
Messages
584
Re: Gas in Crankcase

Any time! Glad we could help out. There is a huge wealth of knowledge here if you ever need anything else.
 
G

gss036

Commander
Joined
Jan 18, 2003
Messages
2,914
Re: Gas in Crankcase

If it worse in cold weather, check the thermostat because the engine is running cold. Replace the thermostat, under$20 for Honda. I had to change mine because of the same problem. The hotter the better if it is used mostly for trolling.
 
C

Crankcase

Recruit
Joined
Jun 6, 2005
Messages
4
Re: Gas in Crankcase

Good Evening Gary,<br />Thanks for the great tip which I will pass on to my friend tomorrow. He's been frustrated for some time now so just maybe! I was away from the computer for most of the day because I have out of town company coming tomorrow so have spent the day trying to make this place look 'not-quite-so-lived-in'! :) I think I'm failing. Will let you know if that is the problem. <br />Thanks Again<br />Marcia
 
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