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Weird engine nock, do i need valve adjustment? BF15a

K

Killerbean

Member
Hi Guys,
Last year due to the help with this forum my honda run great. I have a nice summer :)
Upon inspection today the engine is running fine but.....

i hear a weird engine nock.
Its coming from the rear of the engine.
Last year i gave it a big service package.
But i didnt look at the valves.
engine ran 10-15 hours last year, the oil is level and clear.
I hope that somebody will reckognize the sound and can tell me what it is, i have never adjusted the valves of an outboard before.

Thanks in advance
 
Hi Killerbean,
BF15A?
It looks like a BF15D to me.

Anyway, YES! Adjust the valves!
I say that because it's simply something that needs to done periodically on these engines.

It needs to be done because wear takes place and the valves can be opened too soon and contact the piston. This will damage your engine!

If the noise goes away after a proper adjustment then you'll know that's what was causing it.

Good luck.
 
Im sorry i think its a D, i will adjust the topic title.
Just removed the valve cover.

Measuring everywhere .20 / .25
But i have to grab the manual to see how to correctly measure
i have done valve adjustment on my r1200 motorcycle a few times, but it has been a few years ago.
Yes i will absolutely post the solution
thank you very much for your reply


Edit, i cant edit my first post unfortunately
 
The left side is the intake if im not mistaking correct? :)

100.jpg


IMG-20230605-WA0014.jpg
 
In that photo the intake is on the right (starboard side of engine.)

The intake spec is much tighter than exhaust.

Intake 0.015 to 0.019mm
But set them to 0.017mm

Exhaust 0.021 to 0.025mm
But set them to 0.023mm

Make sure that you have the the valves "on the rock" when setting. Meaning that both valves are closed and the rocker arms loose when you wiggle them.

Get them as close to the "in the middle" adjustment I recommend and make sure the lock nuts are secure when you finish.

PRO TIP:
when ready to make the adjustment, start with the gap slightly loose. Gently snug the lock nut to provide a little resistance and then tighten the adjustment screw.
Doing that will keep your adjustment from changing when you tighten the lock nut fully.
Always check the gap AFTER you tighten the lock nut to see if it changed. Readjust if necessary.

Good luck.
 
Forgot to say your intake valves are VERY loose!
Which is odd...
They usually get tighter due to wear in the valve seat.
Were your locking nuts tight?
 
Hi Jgmo,
Thanks for your reply
i have to wait because the engine is not fully cold yet. I will loosen them tomorrow. If i will do this in a hurry i might break something.
I also have to look for the right tool that fits the square nuts. A size 4 wrench is still too big.
but, i have remeasured just now, with the engine pretty much cold. and this updated photo has the results
All where very tight (exhaust .30 intake .20)
I will measure again tomorrow and try to adjust wil a fully cold engine.
After reading a little bit in the manual it all comes back to me, it isnt rocket sience but it requires some focus.

200.jpg
 
Those clearances are not that far off.----I do not believe that is the cause of this knocking.----Loose valves usually just do a bit of ticking.
 
good day gentleman,
I purchased the valve adjustment tool today and adjusted the valves to spec.
But... unfortunately no solution. It only looks to get worse.
I dont know what to do anymore i spent a lot of money to purchase and service this engine last year.
Had 10-15 hours of fun with it.
To spend a lot of money again this year? :-(



The fuel is new
last year i serviced it with the original honda kit 06211-ZY0-505
 
I think the bolt holding the gear on has loosened and the noise is caused by the clearance on the gear to the key ? A loose flywheel makes the same noise . Check the bolt . .??
 
thanks for your reply.
Yes i do think that there is some space or something wrong with this plastic wheel.
I can do a lot for myself but i brought the engine to the mechanic yesterday.
i will write the solution here.
Lets hope it doesnt cost me a fortune 😅
 
I just got a call from the outboard mechanic.
He told me that this plastic wheel has a crack on the bottom side near the 'wedge' (i dont know the correct word in english)
The replacement parts (wheel+timing belt) are 160 euro's
He told me that everything needs to come off (flywheel etc.)
or that it is possible that i leave it like this, wich is not an option for me. My mechanical hart hurts hearing this noise.
in total its well over 400 euro's. Does that sound like a normal price? I'm handy but i usually dont trust myself working on timingbelts.
 
Final update,
today i have put down a few marks on the belt , pulley and flywheel.
I removed the old pulley, it was rusted to the shaft.
but i was able to simply change out the pulley and leave the timing belt on (4 years old, looking great)
I have attached pictures in this post of old and new, its a 1/1 match.

She runs perfect again !
 
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