MERC 25 XD blows fuel return lines

Brandon Fischer

Recruit
Joined
Jun 15, 2006
Messages
3
I have a merc 25 XD tiller. The fuel return lines that run from the side of the piston wall back to below the carburator are splitting do to pressure. Any ideas would be great.
 

studlymandingo

Commander
Joined
Mar 22, 2006
Messages
2,716
Re: MERC 25 XD blows fuel return lines

Welcome to iboats. How old is the motor? Are the lines old? Have you checked the compression on the motor?
 

Brandon Fischer

Recruit
Joined
Jun 15, 2006
Messages
3
Re: MERC 25 XD blows fuel return lines

I think it is a 84 or 85. The lines are not old, we have replaced them with the correct tubing 2 times. I have not checked the compression with a tester of any kind but it seems to be good when yoy pull it. The motor runs starts and idles great. One idea someone gave us is that the plugs were firing at tdc and bdc and that was pressurising the crankcase and causing the lines to blow. When the lines blow they are somewhat brittle from heat I supposed.and then there is a big split in one side close to where the hose hooks up.
 
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