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Sj410 fuel pump oil leak

Posted: Fri Sep 06, 2013 9:11 pm
by Sj410red
Hi all, been having probs stopping my oil leak, I have removed fuel pump 3 times and made up new gaskets and last time put 2 gaskets back on with gasket sealant on all surfaces, but after a run up, theres still a slight leak dripping onto the gearbox bell housing.
Any ideas gladly welcomed as I'm fed up with the drive being a mess!

Re: Sj410 fuel pump oil leak

Posted: Fri Sep 06, 2013 10:30 pm
by Darrell
Is it possible that the gasket that joins the distributor housing to the cylinder head is leaking?

Re: Sj410 fuel pump oil leak

Posted: Fri Sep 06, 2013 11:37 pm
by Sj410red
Hi, no I've cleaned the area and it's defo coming from fuel pump to distrib housing joint

Re: Sj410 fuel pump oil leak

Posted: Sat Sep 14, 2013 8:20 pm
by Sj410red
After reading some posts on crankcase breathers, I checked mine, the 1 which should go to the air box had a bolt cable tied in the end of it, as previous owner who fitted snorkel had blanked it off, so I've fitted a crank case breather in its place of the blanking bolt, also removed and checked the pressure release valve on top of carb, it rattled on removal but wd'ed it and it rattles bit more now, so I cleaned base of fuel pump, and top of gearbox of oil, tightened fuel pumps bolts just a bit more, test drive, and still it's weeping from that joint! has anyone known of these joints warping thus making them unsealable? All comments welcome, thanks Richard

Re: Sj410 fuel pump oil leak

Posted: Sat Sep 14, 2013 9:01 pm
by Tramp
Is it coming from the joint, or leaking from the bottom of the pump? At the bottom of the pump there is a little breather hole when the pump is worn it leaks a little oil through and drips down onto the bell housing, some people have been known to put a screw in the hole to block it and cure the leak but I replaced the pump

Re: Sj410 fuel pump oil leak

Posted: Sat Sep 14, 2013 9:08 pm
by Sj410red
Hi, I wasn't aware of a breather hole, the oil appears on the gasket line of pump to dizzy joint, I have checked for it running down but can find any trail, where is this breather hole? Is it higher up nearer the diaphram area?

Re: Sj410 fuel pump oil leak

Posted: Sat Sep 14, 2013 9:19 pm
by Darrell
I don't think the 410 fuel pump has this weep hole ??

Re: Sj410 fuel pump oil leak

Posted: Sat Sep 14, 2013 9:30 pm
by Sj410red
Yep that's like my pump

Re: Sj410 fuel pump oil leak

Posted: Sun Sep 15, 2013 6:25 pm
by Sj410red
I've had a breakthrough! After cleaning up pump and running engine up, and a very close inspection, the oil seemed to be coming from the pin which goes thru pump, which is the pivot for the pump arm, so junked that pump n went and raided my rotten sj for a pump, got it off, compared it, similar, but no visible pin showing, slight different design, made up the 7th paper gasket, bolted it on, and presto, no leak ( so far ) !
So if anyone's got an oil leak coming from ther pump, check the pivot pin which runs thru pump, left to right, bolt to bolt, it cud be weeping from that!

Re: Sj410 fuel pump oil leak

Posted: Sun Sep 15, 2013 9:00 pm
by Jordi
Good detective work bud :thumbup:

I love doing the same job half a dozen times too.