Still having can't get 15hp to idle

[boscoe99]

The illustration for the reed valve assembly appears to depict what looks to me like an integral seal. What do you see on your yours?

[yellowtail]

Thanks Boscoe: I've been looking at the carb exploded parts diagram in the manual and it does not show a carb gasket.

In your diagram it would appear to be a rubber ring gasket, (O-ring)... and that may be in place on my engine, just hard to spot under what appears to be gasket goo. I wasn't looking too closely because I wasn't sure what to look for.

From what you have shown me, I should be able to order the part. But right now, after adjusting the idle this morning, the engine seems to run well at speed but still misses intermittently at low speed.

This may be a separate issue.

Thanks for the information; I know you're time is valuable and I appreciate the help.

Bry

[TownsendsFJR1300]

The parts fisch : 2006 and Later 15MSH Yamaha Outboard INTAKE Diagram and Parts

Doesn't show an o-ring even there... Now they put a gasket at the air silencer, but NOT at the reed to carb flange??

Yellowtail, can you look at that reed assembly and see if there's a machined slot for an o-ring?

If so, worse case scenario, you can make your own o-ring. Pump shops carry the material. Simply get the correct size, cut to the correct length, then super glue the ends. Works great..

I don't see Yamaha EVER using just gasket sealer at a critical joint...

The cheapest weedeaters, small engines, etc have carb gaskets there...

[panasonic]

Yellow tail, I believe there is supposed to be a gasket there as well, most likely an oring seal.

The fuel pump pulse hole is on the front carb flange and the face of the intake manifold, if that is not sealed properly it may cause issues. And not to mention the engine sucking air there, possibly making it run lean.

I cant find it the parts diagram either.

[yellowtail]

During World War Two my dad was stationed in India and his job was to keep the fighters in the air, parts or no parts. Supply lines were thin at times and he made gaskets from brown paper shopping bags. When the gearbox came loose on my diesel in some backwater in the Caribbean and chewed up the gasket, I followed his lead. That was in ‘92 and that piece of brown paper is still in my engine and doing a serviceable job.
Thanx Dad!

[panasonic]

I thank your dad for his service.

[boscoe99]

Yellow tail, I believe there is supposed to be a gasket there as well, most likely an oring seal.

The fuel pump pulse hole is on the front carb flange and the face of the intake manifold, if that is not sealed properly it may cause issues. And not to mention the engine sucking air there, possibly making it run lean.

I cant find it the parts diagram either.

If it is integral with the reed valve assembly it won't be shown. Not available for purchase separately.

Lot's of stuff is used on Yams that is not sold separately.

[ECGOERES]

did you get your idle problem fixed yet

[yellowtail]

Engine runs much better... idles. Still some hesitation at low speed, especially when the engine is cold, misses occasionally and the revs drop unexpectedly from time to time. But overall, I'm really happy with the results. I really don't want to remove the carb again but am open to suggestions. Oh, plugs are a nice tan color.

Thanks....

[yellowtail]

I want to thank panasonic for his kind words.

[rodbolt17]

there is either a gasket or an oring between the carb and intake.
usually it is shown on the page marked intake.
why it is not on the carb page only Yamaha knows.
sometimes it shows up on the repair kit one page.

[panasonic]

I want to thank panasonic for his kind words.

Most of those men and women are gone now and we all owe them gratitude for their service.

I had a close relative who served in RAF as tail gunner in Lancaster bombers. He was a great man, but my dad said he was never the same after he came back.

[yellowtail]

Off topic but Dad worked on the Rolles Royce Merlin aero engines used in Spitfires and the venerable Lancaster Bombers… paper bag gaskets and paper clip cotter pins. Keep ‘em flying!

[panasonic]

Off topic but Dad worked on the Rolles Royce Merlin aero engines used in Spitfires and the venerable Lancaster Bombers… paper bag gaskets and paper clip cotter pins. Keep ‘em flying!

They did what they had to...cant be grounding no airplane because you don't have a gasket...war to fight and win.

We had a Merlin engine in the college I trained in to become a Aircraft Maintenance Engineer. What a beast of an engine!! Never got to run it, we did not have test stand or prop for it. I would have loved to fire that up.

Canadian aviation museum has a flying Lancaster and seen that one running and flying....what a sweet sounding aircraft.

P-51 also had a Merlin on it ( later Packard built the same engine under license in the USA), it was a pig at high altitudes before they put that engine on it.

Most of the Merlin's and Packard's are gone now, as they use them for Air Racing in the states, run them at twice or more rated HP and blow them up.

Several times, rich Americans showed up at the school, unannounced, with a pocket full of money wanting to buy that engine to use it for racing.

I am glad to say the engine is still there.