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Honda BF45 fuel pump leaking engine oil

S

seaspearo

New member
Noticed small amount of engine oil leaked out of fuel pump, take the fuel pump off to check oring, it looks ok, no crack and soft, a little squeezed, I had a 1200 pcs oring set, so I replaced the o-ring anyway. The spec said 20.8x2.4, I used closest one 19.2x2.4 from the kit, went out yesterday and noticed there are some engine oil again, will that small o-ring size difference cause trouble? or leak is from somewhere else?

Thanks!
 
Hi seaspearo,

Just guessing really but I would suggest finding a specialty hydraulic shop and source the exact size oring before assuming the leak is from another area on the pump.

I'm in southern California and use a shop in Fontana called
Orings & Things to find stuff like that.

You're right though, the leak could be from another place on the pump but unless you can see it I'd try using the correct size oring.

Good luck and please update with how you get on with the issue.
 
I feel the leak is from fuel pump, since it is engine oil, not gas, the pump is good, so the leak should from the pump and engine block, that o-ring should be the problem. 20.8x2.4 is the Honda spec, what I have is little smaller.

Thanks
 
There are metric sizes, which Honda will be, but maybe you knew that? Can you buy the Honda part- to eliminate that as being the problem?
 
NSDON said:
There are metric sizes, which Honda will be, but maybe you knew that? Can you buy the Honda part- to eliminate that as being the problem?
Click to expand...

Yes, 20.8x2.4 is mm, don't feel 1mm difference will cause trouble, they looks identical in naked eyes. I feel the leak might coming from cylinder head gasket, I opened the cylinder head cover, gasket is in good shape, but the gasket sealant kind of gone and some brittle pieces, so just ordered HondaBond 4 and will let you know if that fix the problem. Basically cylinder head and fuel pump are only two places engine oil leak can happen, right?
 
I mean crankcase valve cover. My leak is in right bottom of valve cover and fuel pump area. Just watched this video, he put the cover back without apply the sealant, he missed it or no need for sealant?
 
This gasket is a rubber gasket, can I reuse it with sealant? or need be changed like he said as one time use? Or get a new one and put on without sealant?
 
I’ve reused them if they look good, no soft spots or uneven areas visually. I use a non setting product, nothing that dries hard and rubbery. I use Hylomar Blue or a marine synthetic grease as a sealer on gaskets, rubber or paper type. The RTV type becomes small bits of rubber which can clog passages or sensors.
 
NSDON said:
I’ve reused them if they look good, no soft spots or uneven areas visually. I use a non setting product, nothing that dries hard and rubbery. I use Hylomar Blue or a marine synthetic grease as a sealer on gaskets, rubber or paper type. The RTV type becomes small bits of rubber which can clog passages or sensors.
Click to expand...
I will try to reuse the rubber gasket, I already ordered the HondaBond 4, service manual said use three bond #1215, three bond is out dated and expensive, I think HondaBond is replacement.
 
bobmech said:
You should use a small amount of the Hondabond or RTV only on the corners of the arches.
Click to expand...
It is interesting you pointed only apply in corners of arches, sealant is just for sitting the gasket? when I took the gasket off, I only saw some grey sealant in the corners of the arches on the cover. I thought majority of the sealant are gone, that is why I thought I need reseal the gasket even though this is rubber gasket, works based on compression seal. This is from service manual, it said apply on mating surface.

Reassembly:
Apply Three Bond #1201 or #1215 or equivalent to the mating surface of the cylinder head cover and the cylinder head.
 
I applied Hondabond and let it set for two days, just run the engine for 15 minutes, the leak is fixed.
 

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If leak returns, I will get a new gasket. I know I should better to get a new gasket, but already ordered the Hondabond and want just give it a try. Very hard to apply a thin layer, gasket is big and need do it quickly. Did cause some mess on the cover.

Thanks for help!
 
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