For those of you that don't think it can happen to you, please think again. I was on the phone with Don earlier today discussing an issue with my motor and he suggested that I at least take a look down the plenum to make sure the little yellow cap on my flywheel wasn't in there. Well, guess what? Take a look at the pic!
[IMG] http://s412.photobucket.com/al...8.jpg [/IMG]
I got it fished out, and we'll see if I see any performance difference tomorrow.
Thanks Don!
Rusty
MSG (R)
Louisiana National Guard
Desert Storm, OIF Veteran
08 21XDC/300XS
Perhaps we should rename the post "My little yellow enemy"
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RustyJ671 »</TD></TR><TR><TD CLASS="quote">[IMG] http://s412.photobucket.com/al...8.jpg [/IMG]
I got it fished out, and we'll see if I see any performance difference tomorrow.
Thanks Don!
</TD></TR></TABLE>It will!!!!
Do all the engines have a cap over the nut? I pulled my cowling and the one plastic cover over the flywheel and no cover. Just a bare nut. Did not pull the other intake housing to look down into it. Should I? Could not see cover anywhere inside the cowling.
The engines are ALL supposed to leave the factory with the "little yellow plug" installed in the center hub of the flywheel.
It must be removed to lift the engine out of the crate.
The purpose of the yellow cap is to help prevent water from getting into the threads, which can cause corrosion. Grease is also applied inside this "cap". This has been the practice (using the same little yellow cap) for my entire "career"... and even longer than that.
Presumably, some of these caps are simply left "loose" inside the cowling. Others are presumed to have been "spewed off" their "flywheel throne" as the grease heats up, builds pressure under the cap, and forces them out of the flywheel.
UNLESS the boat is used in a saltwater application, I tend to "remove the yellow cap, apply a light coating of 2-4-C grease to the threads, and toss the yellow cap into a very special coffee can on my workbench".
It's rare that this happens... but I think this one is "#6" that I've heard of in the last year or so....
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Yes, what years did they start with this yellow cap?
518 DVX
"As far back as I can see in the parts book" (and as far back as I recall, which is about 10 model years back from my 34 years as an "apprentice").
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
I have seen them on late 70's and early 80's plenty of times!
Mine is an 02 opti and have not seen this on the nut. Could be hanging around some where,hope it was never put back on. So how do I get at the plenum to see? Engine has been running OK.
Thanks
518 DVX
Inspecting for the plug inside the plenum only takes a couple of minutes...
As others will attest (several of our BBC members have fallen victim to this little yellow "culprit"), if it's in the intake, you WILL be looking for a solution to a performance problem (you'll know that SOMETHING is wrong).
Complaints range from "this is the sickest motor I've ever run" to "motor sputters or skips at WOT" or "runs fine one minute and terrible the next".
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
That little yellow plug sure caused Don and I a lot of problems on my previous motor!!!!!!!!!!! Hard to beleive that a .05 cent cap could cause several thousand dollars in problems..
I was able to get the boat on the water Monday and it ran better than it ever has. I went from running 5900 rpms with issues to running 6100 and bumping the limiter on the same prop. I even heard the Smartcraft beep a couple of times. Thanks Don!
MSG (R)
Louisiana National Guard
Desert Storm, OIF Veteran
08 21XDC/300XS
Great! Let's get that prop bumped up a bit... and put those extra RPM's to good use (as well as eliminate the overspeed faults)!
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Just got my 27" Trophy back from Jay Martin today. I was turning this stock prop to 6100. Now it is a 28" B&B. I hope to get to run it this weekend if the current storm system doesn't blow us away tonite.
MSG (R)
Louisiana National Guard
Desert Storm, OIF Veteran
08 21XDC/300XS
I know this is an old thread, but I still see guys that haven't taken a look down into the intake.
MSG (R)
Louisiana National Guard
Desert Storm, OIF Veteran
08 21XDC/300XS
I guess if you don't have a little yellow cap on the nut ,you need to start looking.
OR, speak with whomever rigged the engine to determine if it was REMOVED at the time of rigging (and safetly placed well outside the cowling).Originally Posted by Lpolk
I guess if you don't have a little yellow cap on the nut ,you need to start looking.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
I had the same issues, little yellow cap = broken reeds and a slew of other problems! Definitely worth the time to take a look! Also, you might not be able to see the cap, as mine was lodged in a #6 reed cage, but my #4 cyl. reeds were the ones broken. Pretty sure it had been floating around the intake plenum for the entire life of the motor, until I purchased the boat. 786 hrs when I purchased!!!! And Don helped fix it!!!
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