Mercruiser 305 Fuel leak

[smiles16]

Hey guys I had a post a while ago where I mentioned this, but it wasn't the main topic....

I have an '86 mercruiser 230 (305ci) with a Quadrajet. It had a fuel leak at the carb inlet when I bought it, took it apart and found the gasket and fuel filter were missing. So I picked up a new quicksilver filter kit that came with a new screen filter and two washers/gaskets. One large one and one small one for the inside.

Looked up some pics of these carbs on google images and I didn't see any of them using the large oring on the inlet. Which is it? I didn't use any teflon tape or pipe dope on the threads. Should I have?

Also, noticed on pics of other engines, the large spring attached to the throttle is attached to the front of the engine.... mine is attached to the rear. With that said, throttle will not return to seat with the idle screw on its own. Is this the problem?

Thanks, I'm not a chevy guy so I'm a bit lost.

 

[Bt Doctur]

There are no O rings used. there is a thin flat washer for the big nut. Should not need ant sealant on the threads, the flare does the sealing
The carb return spring is just that a "return spring" in case the throttle cable breaks. the spring CLOSES the throttle

 

[smiles16]

I shouldn't have said o-ring. What I meant was washer. The kit came with two of them. One for the inside of the inlet nut, the other (I assumed) for the outer area between the carb and the wrench flats. So I guess I should omit the large one?

And thanks for verifying the spring. My common sense told me that was wrong, my paranoia told me to ask y'all first.

 

[smiles16]

No Title

This is the kit I used.

 

[Bondo]

Ayuh,.... The little washer gasket seals the filter, the larger seals the big nut to the carb body,....

 

[km1125]

Agree with BtDoctur and Bondo. No sealant or tape, use the large flat washer to seal the adapter to housing and the small gasket to seal inside between filter and housing. Not sure on yours, but some have a spring inside to hold the filter tight to the gasket. On yours the filter may be large enough not to need that, but if it is not then no sense in putting the filter in without the spring as it would not be held against the gasket and would not do anything.

ALSO, when putting the fuel line back on, make sure you don't cross thread it (there's a couple other threads in iboats on this). This is on the flare fitting that goes from fuel pump to carb inlet.

 

[smiles16]

Well I've done all of this. The flare looked great, the washers are where they are supposed to be, and I still have a leak at high throttle. It's dripping from the large inlet nut. I tightened it pretty good too. Maybe the threads are worn?

 

[km1125]

Well I've done all of this. The flare looked great, the washers are where they are supposed to be, and I still have a leak at high throttle. It's dripping from the large inlet nut. I tightened it pretty good too. Maybe the threads are worn?

Post a pic with an arrow where you are sure the leak is. Are you sure it's leaking between the big nut ("Adapter") and the housing?

The threads do not seal anything. If the nut is tightening down on the gasket, it should seal there.

Is it possible the housing is cracked? Is it possible the area where the gasket is trying to seal is buggered up so it can't seal?

 

[smiles16]

Well I don't have any pics on me, at work, but I'll google one up, draw and post.

 

[smiles16]

No Title

Dripping from the inlet nut down into the valley

 

[km1125]

Yea, that's where I thought you were talking about.

Check the body and the adapter for cracks. They can happen if the adapter is overtightened, especially if someone was not using that gasket. Also, take the adapter out, remove the filter and both gaskets and hand tighten the adapter back in. Check for a gap where the large gasket should be. If there is not a gap there, then there should be enough pressure on the gasket to properly seal. I'm betting your have a crack.

 

[smiles16]

Boy a crack would sure make my day.... I'll give that a try next chance. I would think the threads would strip before a crack.

Well if anyone else has more ideas, I'm glad to hear

 

[smiles16]

Thought I'd update:

I checked and didn't find any cracks, and my threads were great. Went down to the local auto parts store and picked up a nylon washer and swapped out the steel one..... fixed 'er right up.

Got to run it this weekend though and some new issues reared their heads... starting a new topic for that.


Thanks for the help guys!

 

[km1125]

Glad to hear it! and THANK YOU for coming back and posting the resolution... too many don't do that and leave everyone else hanging as to whether or not the problem was ever resolved!

That washer should not have been steel... should have been a fairly soft metal like copper. I'd be curious enough to look at it with a magnifying glass to see what was wrong with it (if it was steel though, then that's why it didn't seal!)

 

[smiles16]

Whatever it was, it's what came with the quicksilver kit. Could also be that the carb is old and original. Mating surfaces may have just enough imperfections for that to not give a good seal.