2017 Mercury 150 need valve adjustment procedure

MrTim

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Mar 2, 2022
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Hi all,
2017 Mercury 150 with about 450 hours
I've searched the threads and haven't really seen what I'm looking for..
Recently, my 150 has started to sound a bit like a sewing machine while at idle so likely needs to have the valves adjusted. I searched the forum and u-tube and only found bits an pieces of info that conflicts itself. Some posts suggest they are not adjustable and/or may need shims vs adjustment.
Does anyone have a procedure or link that explains the valve adjustment process on this series of outboards. I've successfully adjusted valves on other outboards but a bit cautious as I couldn't locate a procedure for my 150.
Any suggestion is much appreciated,
Mr Tim
 

MrTim

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Mar 2, 2022
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I found a procedure in a borrowed service manual. I'll attempt to scan the procedure and post for any others who may have similar question.
Mr Tim
 

QBhoy

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Hi. I’m going to go out on a limb here…and suggest that it’s ridiculous unlikely that such a thing is the cause of your issue. It’s much more likely that it’s caused by more well known things on these. Like the HP fuel injection rail fuel filter insert needing cleaned or replaced. Spark plugs or thermostat issues causing cold running to throw fuel past the rings into the oil. There are a few other culprits too. Shift switch issues caused by throttle cable assembly miss alignment, tps failure, poor fuel, neutral safety switch failing or remote cables binding…to name a few.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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I found a procedure in a borrowed service manual. I'll attempt to scan the procedure and post for any others who may have similar question.
Mr Tim
I would suggest you do not post copyrighted material
 

MrTim

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Scott D,
Thanks for your response. But are you sure you've responded to the right post? To me, the sound I'm hearing sure seems like the mechanical sound of tappets needing adjustment. Are you suggesting that its unlikely that the valves would ever need adjusting? Some of your suggestions seem like possible solutions to a engine with running or performance issues. My issue is what seems like mechanical noise, otherwise the engine runs perfectly at all RPMs.

The reason I ask is that there was so little information on valve adjustments that maybe valve adjustments are rarely needed. Am I going down the proverbial rabbit hole? I've been there before:)
 

boscoe99

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I would suggest you do not post copyrighted material
Members of all forums say they hate thieves more than anything in the world but when it comes to copyrighted data owned by others they seem to have no problem stealing data or sharing stolen data.
 

boscoe99

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Aug 22, 2013
Messages
1,965
Hi all,
2017 Mercury 150 with about 450 hours
I've searched the threads and haven't really seen what I'm looking for..
Recently, my 150 has started to sound a bit like a sewing machine while at idle so likely needs to have the valves adjusted. I searched the forum and u-tube and only found bits an pieces of info that conflicts itself. Some posts suggest they are not adjustable and/or may need shims vs adjustment.
Does anyone have a procedure or link that explains the valve adjustment process on this series of outboards. I've successfully adjusted valves on other outboards but a bit cautious as I couldn't locate a procedure for my 150.
Any suggestion is much appreciated,
Mr Tim
Have you looked in the Mercury service manual for your specific model?

Unless your motor uses hydraulic lifters, which I doubt, there will be an inspection and adjustment procedure for measuring and setting valve lash. In some motors it might be repositioning a screw and in others it might be removing and replacing shims or valve buckets.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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49,574
Scott D,
Thanks for your response. But are you sure you've responded to the right post?
Yes, sharing copyright material is illegal.

Are you confusing my post with Qbhoy?
 

QBhoy

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8,342
Scott D,
Thanks for your response. But are you sure you've responded to the right post? To me, the sound I'm hearing sure seems like the mechanical sound of tappets needing adjustment. Are you suggesting that its unlikely that the valves would ever need adjusting? Some of your suggestions seem like possible solutions to a engine with running or performance issues. My issue is what seems like mechanical noise, otherwise the engine runs perfectly at all RPMs.

The reason I ask is that there was so little information on valve adjustments that maybe valve adjustments are rarely needed. Am I going down the proverbial rabbit hole? I've been there before:)
Hi. All I’d add, is that having to adjust such a thing, at its age or likely hours (if at all) is far from the normal. Unheard of even, as far as I’m aware. I have the 2.1l version around the same age. She’s done 1400 hours to date.
But I can maybe also say that my engine has previously made a ticking noise at idle and also running poorly at the same time too. It was caused by an electrical short, that was affecting the ignition system. As a result, it was throwing unburnt fuel into the oil, thinning the oil down ! Thankfully caught it in time and is now ok with fresh oil.
I’d like to hear the noise from yours, if possible. The fuel injection system can also make a slight ticking noise if the hood cover is off. Won’t go into it too deeply just now…but a few wee niggles can result in poor electrical and ignition form, resulting in diluted and thinned oil. Trim pump motor shorting, trim wiring and/or switch, occasionally shorting. Also well known is for the shift switch under the gear and throttle cables, failing or compromised, by the requirement of a cable assembly mechanism adjustment in there. That can cut the ignition randomly, not always noticeable, but either way…throws fuel into the oil. The neutral safety switch in the remotes can intermittently fail, causing intermittent ignition or rpm limiting, throwing fuel into the oil again. A loose or stray tank 2 sender wire can also find its way to dangling into the bilge and shorting out too. Causing…guess what ! Haha.
 

MrTim

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Mar 2, 2022
Messages
9
Qbhoy and Scott D,
Thanks for your suggestions. Since my Merc is running perfectly and the only symptom is a bit of noise at idle, I'll postpone the possibility of adjusting the lifters at least till fall maintenance time.
Again, thanks for your inputs, much appreciated.
Scott D, I did in fact mistake your response, my apologies.

Thanks to everyone,
Tim
 

QBhoy

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Mar 10, 2016
Messages
8,342
Qbhoy and Scott D,
Thanks for your suggestions. Since my Merc is running perfectly and the only symptom is a bit of noise at idle, I'll postpone the possibility of adjusting the lifters at least till fall maintenance time.
Again, thanks for your inputs, much appreciated.
Scott D, I did in fact mistake your response, my apologies.

Thanks to everyone,
Tim
No worries Tim. Try changing the oil I’d say. Easily thinned with fuel, depending on temperatures you run in especially. Put your ear next to the injection gear too. See if it might be that you’re hearing. I find that these things are so quiet running these days, that it’s very to hear all sorts of noises from them that are otherwise hidden on a less refined engine, of older generations perhaps
 
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