O-ring woes!

[petrolhead]

Just had what should have been a great days boating ruined by the failure of a single 50 cent O-ring!<br />Took my boat out this morning and noticed almost immediately that the fuel line connector was leaking (this is on my Johnson 18), on inspection I found that the fuel line O-ring had completely split, and the one on the air line had a split starting too. These were brand new OMC O-rings fitted just a few weeks back and they've both failed already!<br />If I could think of a way to do away with the connector completely I would, but I need to disconnect the tank to fill it up at the gas station, and to remove the motor of course, so it looks like I'm stuck with these mickey mouse O-rings!<br />Now, I can order them in the UK from Keypart, but they take at least 2 weeks to arrive, can someone please recommend a US supplier who will ship to the UK (not iboats) without charging a small fortune to do so? I'm going to buy a dozen of these little buggers and keep them on my keyring for when they inevitably fail again!

 

[Paul Moir]

Re: O-ring woes!

<br /><br />If you can find it locally, the o-ring is a metric one - 5mm ID x 3mm Wide (OMC PN 301824, Aftermarket pn 18-7111 each). Viton would be good.

 

[petrolhead]

Re: O-ring woes!

Ah, now I didn't think to look for a metric equivalent ring, good idea! What's Viton, is that a manufacturer or a material?

 

[Paul Moir]

Re: O-ring woes!

Material - it's a brand name for a fluoroelastomer. I think the original ones are nitrile which may be easier to find, but it is not as durable. <br />It's funny, but I've noticed a few metric parts on these OMC engines. I got suspicious when I went to find some for myself, and the ID is listed as .197" and the width as .118".

 

[R.Johnson]

Re: O-ring woes!

You can convert this engine to the single line system with a fuel pump. I have made this conversion by using the fuel by-pass cover from a mid-70's, 25 HP. This, I feel makes the engine more reliable, and safer. I don't like those old double line tank's. The last one I had come into my shop, I forgot to check, and see if the fuel cap was open, The next morning I had a 6 ft. puddle of fuel on the floor after the fuel hose burst. That's not good with a gas fired furnace in the building.

 

[petrolhead]

Re: O-ring woes!

OK Paul, I've had a look and the nearest I can find is 5.6mm ID x 2.4mm wide in nitrile rubber, not sure if those will work or not, maybe a bit too sloppy.<br />In Viton the only ones I can find are Imperial sizes, the nearest would be 3/16" (4.7625mm) ID but only 1/16" thick.<br />I thought about converting to single line R.Johnson but have several objections, firstly the old pressurised system works very well normally, it's original and I do like to keep things original if at all possible.<br />Secondly there's the cost, a fuel pump, new tank and fuel line, new connector etc..., not easy stuff to get over here and therefore expensive.<br />Once in a while I may forget to crack open the cap at the end of the day and release the pressure, but the boat lives outdoors under a tarpaulin so no real fire risk, and I do check things like fuel lines regularly.

 

[Devilfish]

Re: O-ring woes!

Petrolhead,<br /><br />Can you give me the EXACT size of the rings you are looking for?<br /><br />I work with a company in the plastics industry. They MAKE 'O' rings. I can see if they can come up with a replacement. We also have a lot in stock (about 5000 diferent sizes) at one of the companies I work for. <br />They just let me help myself to any I want.<br /><br />Can't promise anything but I can try and help out if you like. <br /><br /><br />Regards<br /><br />Ian

 

[petrolhead]

Re: O-ring woes!

Cheers Ian, the size is 0.197" ID x 0.118 wide, which as Paul pointed out is 5mm x 3mm. They are fat things, like a doughnut, not like the usual plumbers O-rings.<br />I just checked the connector with a micrometer and the "spigots" are 5.4mm diameter, so the 5.6mm ID ones I found would be useless.

 

[Devilfish]

Re: O-ring woes!

Ok, I will have a look in stock tomorrow. How many do you need? Would a couple of dozen be ok?<br /><br /><br />If i can get them you can let me have an address and I will post 'em to you.

 

[petrolhead]

Re: O-ring woes!

A couple of dozen would be great if you can get them, let me know what I owe you.

 

[alcan]

Re: O-ring woes!

Petrolhead<br />Did you disassemble the fuel line connector to install the new O-rings? Or did you try to poke them in through the holes?

 

[cajun555]

Re: O-ring woes!

Petrolhead, Just replaced both o-rings on my old connector. Purchased them at OMC dealer. I'll make sure I keep an eye on them. The bag they came out looked pretty old.

 

[petrolhead]

Re: O-ring woes!

Alcan, I poked them in through the holes, I lubed them first though and they slipped in easily, they weren't damaged through fitting if that's what you're thinking and they've been working fine for the last few weeks.<br />I think it's just connecting and disconnecting that's damaged them, with the new rings fitted the connector was quite a tight push fit.<br />Cajun555, mine were genuine OMC parts too, although the bag looked fairly new, I think if you lube the prongs on the male side of the connector with a smear of Vaseline it may help to prevent damage. When new they just seem to be too tight and it takes some force to connect.

 

[alcan]

Re: O-ring woes!

Sorry Petrolhead<br />Those litte fat o-rings will be damaged installing them that way. The brass bushings,washers and stoppers also get burred up durring this incorrect process. Disassemble the connector and do a proper installation, your o-rings will last a whole lot longer. It is so much easier and faster to do the job this way any how. Also check the male connector for burrs.

 

[petrolhead]

Re: O-ring woes!

Well you may be right alcan, I think I'll try one of those jigs that you and Paul mentioned previously and press the brass faces out next time.<br />It did stike me though that the connector was a very tight fit when the new o-rings were installed, I had to press quite hard to get it to click into place, that didn't seem right to me, almost like the rings were too small or the rubber too hard.

 

[petrolhead]

Re: O-ring woes!

I'm going to make this jig tomorrow, just want to check I have this all clear. The brass bushings are pressed out using a rod that goes into the hose connections on the back, yes? So it needs to be about 0.075" or 2mm diameter?<br />And I assume I should pick the old rings out first?

 

[Devilfish]

Re: O-ring woes!

Petrolhead,<br /><br /><br />I should have your o rings by close of play tomorrow. Will give you an update tomorrow evening.<br /><br /><br />Ian

 

[cajun555]

Re: O-ring woes!

Petrolhead, I read the post about the jig using finish nails. The nails were to big to fit in the hole on the connector. I used a allen wrench, butted it against opposite end, cut excess length off the allen wrench. Put in a vise with a socket to catch everything. Worked real well.<br /><br />BTW, My new o-rings were a real good fit. I don't have to force connector onto motor.

 

[alcan]

Re: O-ring woes!

Hi Petrolhead<br /> No, you do not need to remove the o-rings first. Correct, you push the innerds out from the hose end. This requires a slim long punch. Cajuns idea of an allen wrench is good. I think I used a motor cycle spoke for my last one. I have used many things over the years. Cut your punch just long enough to do the job. If they are too long they tend to break. Keep this in mind when choosing material for the punch. It must be tough but not too brittle. I like Chinewalker's technique of using the vice as a press. You will need to compress the spring and the o-ring some what if you tap/drive the guts out. This can be done with a some what extended type blow. Cajun was a bit confused. The finish nails are used as locating pins in the jig, not for the punch. I belive OMC offered this jig tool set-up as a special tool for their dealers and repair centers years ago. I did not invent it. One of my mentors showed me how it was done. In order to get that jig, I would have had to buy the entire shop. So I just made wooden copies. They usually break after a while. If you take the time, make an aluminium jig.

 

[cajun555]

Re: O-ring woes!

Sorry Alcan, Its been several weeks since I read the post. But even with my vice I had a tuff time getting bushings out. But I know for a fact the o-rings haven't been replaced for 30 years. Good luck PH.