Yamaha f250 Start Up Noise

[shotgun16]

Hi Everyone,

I was wondering if I could get some help/input. I have twin Yamaha F250B's that were manufactured in 2008 and purchased new in 2012. They have approx. 300 hrs on them. Mid season last year I noticed the starboard engine upon cold start up would make an odd noise. When cranking the engine the starter would engage normally but upon key release would briefly make a kind of a scraping/grinding noise, and then the engine would run normally. It would only do this on initial start up, once shut down and cranked again it was fine indefinitely till it sat for a while and got cold again. I inspected the engine and noticed the flywheel shrowd was on kind of crooked, figured that might by interfering with the starter disengaging. Repositioned the cover and it didn't do it again for the rest of season, figured problem solved.
Fast forward middle of this season does it again, inspected flywheel shrowd, was on correctly, removed shrowd and started cold, still made noise, figured problem was with starter not disengaging properly. (teeth on both starter and flywheel looked absolutely fine) Motor under warranty so had starter assembly replaced. Figured it would fix problem, didn't make noise initially, then it started again. Thought it could be a problem with the key switch sticking, so I reversed it with the other motor, still did it on port key switch(port engine starts completely normal). Again noise only occurs upon first start up when motor sits for a while and gets cold, there after it cranks fine with no abnormal noise. Also seems to do it more frequently in cooler weather. Any opinions on what the problem might be or a direction in which to look would be greatly appreciated.

[Danishboater]

Dont know how twins are connected,but could it maybe be something with a bad connection for that engine who teases you!!?

If a starter is not getting the right power it can make noise!

[TownsendsFJR1300]

If you can, get a helper (on muffs) and have then turn the key to start.


You now observe the movement and or any sticking /hanging up between the flywheel and starter gears. If its sticking, it should be pretty obvious.

Sounds like when its cold the starter isn't releasing from the flywheel.


http://www.boats.net/parts/search/Ya...TOR/parts.html

[robert graham]

Maybe inspect/clean/lubricate that Bendix on top of starter to insure it's moving up and down freely....I put just a bit of lithium grease on flywheel teeth to make starter teeth engage smoothly....I've also seen the bolts that hold the starter on the motor get slightly loose and need tightening....

[rodbolt17]

pretty normal for the variable cam timing engines.
its kinda normal to hear the cam mechanisim chatter until oil pressure is built up.
have the OCV filters been changed ?

[shotgun16]

Ocv filters have not been changed yet following yamaha maintance schedule, three years on engines since purchasing new. Any risk of engine damage in that scenario rodbolt?

[shotgun16]

Find it weird that one engine does it and the other one does not

[boscoe99]

Have three or more motors installed and it only gets worse given that no two motors almost always never operate exactly the same.

So, is it the motor making the noise that is the problem or is it the motor not making the noise that is the problem?

Or is there no problem at all even though they don't make the same noise?

Now take a twin engine piston airplane with two magnetos per engine. Is the mag drop when one magneto on either motor is turned off going to give the same results? Will two constant speed propellers hold the same RPM at the same times? Will the throttle handles always align?

Now is the fact that the F250 races when it is first cold started a cause for alarm whereas most other Yamaha's do not? Many seem to think so.

[99yam40]

way too many questions for this early in the morning
But it has some good ones

Maybe change the Ocv filters to see if that makes a difference,
it may get them both making the noise or stop it on both, who knows

So, is it the motor making the noise that is the problem or is it the motor not making the noise that is the problem?

Did the shop tecs hear it when you had it in for service?

[shotgun16]

No, just described it to them, they assumed it was bad starter and sent someone to swap it out

[zenoahphobic]

No, just described it to them, they assumed it was bad starter and sent someone to swap it out

It sounds like starter hangs on for a while (as stated by others).

If they changed the starter then appears something NQR with the mounting or flywheel teeth. Have a real close look at the meshing of the starter gear with the flywheel gear (and grease does not help as stated). Putting fine paper between the two can show a tight fitting.

You do this by hand rotating the pinion gear to make it rise to mesh.

You have the other engine to compare with.

Oh slightly oval or out of round flywheel can do this. you will probably need to pull the spark plugs and slowly rotate engine by hand as well (need extra pair of hands to do this!)

[rodbolt17]

trust me, its the variable timing sprockets.
sometimes after sitting they bleed down and chatter like crazy at startup.
dirty/clogged OCV filters make it worse.
find a trained tech that has worked with Yamaha's variable timing system.

[robert graham]

I'd be prone to just go with whatever Rodbolt says....he's the doctor on these motors!...

[TownsendsFJR1300]

I'd be prone to just go with whatever Rodbolt says....he's the doctor on these motors!...

Agreed ^^^

A Proctologist, digging deep, knowing what to look for and magic fingers

[shotgun16]

Thanks for the advice, ordered some ocv filters and will have them tomorrow, will swap them and see if it helps, if not will pursue with yamie tech starting with the possibility of rodbolt's suggestion, will update based on what happens.