Yamaha F100A 2001 Four Stroke Fuel Enrichment Valves

[NZ_Diver]

I have a 2001 Yamaha F100A four stroke outboard. It was serviced just before the end of 2015. We have since had problems with water in fuel and fouled carbs. Water problem has been remedied and I have stripped the carbs and cleaned and serviced. I took it back to the Yamaha service shop to be synced and balanced, only to find that the Fuel Enrichment Valves are leaking at the top and need replacement O-rings. Yamaha Parts advise that there are no O-rings available as a spare part and will need to replace the entire Valve!!!!!$$$$$$
I am amazed at how Yamaha can do this as a cost of about $350 each instead of supplying a 30 cent O-ring!
Does anyone know the size of the O-rings (top cap) or a source of these to replace??

 

[tommarvin]

Tear it apart and get the O-rings, so you know what size, thickness etc. your looking for. You can find a O-ring to replace it, if not the forum will find it for you.

What's a fuel enrichment valve?

 

[GA_Boater]

I can't help on the size, but you can size the O-ring by taking one to a hardware or auto parts store and comparing their stock - As long as the rings aren't captive and non-replaceable. Just get fuel resistant O-rings. I won't swear to it, but Viton rings a bell.

 

[GA_Boater]

What's a fuel enrichment valve?

I think it's item 35 and Yamaha calls it a Prime Starter Assy. 339.95 USD is all they want for it.

 

[NZ_Diver]

Re: What's a fuel enrichment valve? Yes it is the complete unit as shown above. (Thank you GA_Boater). I have a diagram also showing this listed as Electrothermal Valve Unit. Interesting note that my parts diagram (attached) shows another O-ring #9 which is the critical one that 'Im after and yet it is missing from the GA_Boater pic. The local dealer has suggested that Yamaha sometimes missed small specific parts such as this. It doesn't make my job any easier.

 

[GA_Boater]

Not bad for guessing. It was a guess, Diver.

I would remove the retainer and pop one out. Roll the O-ring off and start comparing. As I said earlier, try an auto parts store. The ones here have some large selections. So do our hardware store. Also big box store like Home Depot, if you have any in New Zealand.

Since it's shown as a separate part, you would think it would be orderable.

Is your picture from a factory service manual? Our views are slightly different, but I may have picked the wrong motor. My pic is parts breakdown for a carburetor.

 

[NZ_Diver]

I have now removed the valve from the carb and will remove the O-rings to measure. We have a good source of O-rings here in NZ without problem, but my question really is about brands/manufactures that build or install brand only size parts compelling owners to then obtain only there product. For major parts and components I can see and understand this, but for O-rings?????? I was asking here because I'm sure other owners would have encountered this problem and thought that Yamaha would have provided a remedy or solution. Scarey to think that people would pay $350 - $600(NZ) for a replacement Valve instead of an O-ring.

 

[GA_Boater]

All marine parts are over priced because the manufacturers have us over a barrel. I think their marketing philosophy is why make a dollar profit when they can get 50% more profit.

I guess I misunderstood your original post. So I'm 1 - 1 on guesses in this thread. :doh: I don't know the size of the O-rings. Your good suppliers should be able to help you avoid Yamaha,.

When you find them, get some spares. The others may be going bad too.

 

[lakensea]

Those valves have been used for many years by pretty much all the outboard manufacturers. I've sold & serviced many engines with them and never had an o-ring failure. That being said, your best bet would be to visit your local Honda outboard dealer as they do list them separately. That way you will have the proper size & material.

 

[tommarvin]

Good for you, you were right, tear it apart ,get some O-rings and fix it.
I tear everything apart first, looking for the problem, broken O-rings, seals, gaskets anything out of the ordinary, then find the parts.

 

[GA_Boater]

Those valves have been used for many years by pretty much all the outboard manufacturers. I've sold & serviced many engines with them and never had an o-ring failure. That being said, your best bet would be to visit your local Honda outboard dealer as they do list them separately. That way you will have the proper size & material.

That's good to know if this comes up again. Thanks, Lake.

 

[tommarvin]

Lakensea, this is a Yamaha F 100A 2001 4 stroke, not a Honda.

 

[GA_Boater]

Tom - Lake said the same primer start/enrichment system is used on Honda, Yamaha and others.

It makes sense because Honda/Yamaha/et al don't make carbs.

Keihin and Mikuni, maybe a few others, make most of the carbs for Japanese recreation/outdoor products, even Mercury outboards.

Outboards, motorcycles, lawnmowers, weed whackers, etc. use Keihin and Mikuni carbs.