HOW do YOU Access # 4 spark plug on new Merc 150hp 4-stroke outboard.

ThorSen

ThorSen

Active Member
Aug 17, 2017
219
Western North Carolina
Boat Info
2018 SPX 190 OUTBOARD 150
Engines
150 4-stroke Mercury outboard
Greetings CSR from the Great Smokies where the leaves are (finally!) startin’ to put on their show!

I did a quick search first but, came up empty so, here goes,

WHAT COMBINATION OF ratchet devices (universal joints? Flex shafts? Black magic, voodoo? Incantations?) do you use to get a socket onto - and then extract - the # 4 (bottom-most) spark out of a 2018 Mercury 150hp, 4-stroke?

I just winterized our new Mercury 150hp 4-stroke today and, I LOVE THIS ENGINE (hands down friendliest DIY engine)!!!

Prop off, drain and refill lower unit gear lube - Check

Engine oil drained, replace oil filter and fresh new engine oil - Check

Replace Fuel filter - Check

Pull spark Plugs for Inspection - NOT # 4 !!!!!!!!!

Holy cow, I sat there trying to figure out just what in Hades anyone was thinking bringing the side of the lower engine compartment up PAST where the # 4 spark plug is situated! :eek: o_O :mad:

Anyway, if anyone can describe to me what combination of ratchets YOU use to extract that lowest # 4 spark plug (thinking I need to go by a flexible shaft?) I sure would appreciate it.

(So would my dog - he wants to go for a walk but, I gotta get this last plug pulled! (har-har! :p
 
I'm going to chime in, even though I don't have that engine, nor professional experience as an outboard marine mechanic. Feel free to ignore or disparage my thoughts.

My outboard is no where near your engine, but when I need to get to the bottom of the engine, my lower cowl comes off in two pieces. Maybe yours is the same and removable, though removing it to change a fouled plug when on the water seems like poor design. This is what I had to do... 1) Remove Upper Cowl, 2) pull the plate that holds the trim switch in the bottom cowl and remove switch, 3) remove the hardware on the three latch points, 4) lift and split the bottom cowl in half to remove... I felt like replacing water lines since the old ones looked horrible, and that is what I did for easier access. Only reason I knew I could do that is I went to marineengine.com and pulled the parts diagram and saw that the lower cowl was separate from the rest.
 
Howdy, CNYBoater and I certainly am not going to ignore your feedback and no way would I disparage.

I am going to locate the “exploded” drawing of my power plant in the hopes I may be so lucky!

THANK YOU (and, Hey, Happy Halloween, too! :)
 
I'd probably have to be there looking at (or maybe some pics), as I haven't worked on one of those, yet. But... is there room for you to at least get a spark plug socket on it? You can get sockets that have "flats" for an open end wrench at the end you would normally put the socket wrench on. If you can slip a socket over the plug, that should work for you.

I am sure that lower cowling is removable - the question will be how easy it is, anymore. Worth checking into, though.
 
Lazy Daze said:
I'd probably have to be there looking at (or maybe some pics), as I haven't worked on one of those, yet. But... is there room for you to at least get a spark plug socket on it? You can get sockets that have "flats" for an open end wrench at the end you would normally put the socket wrench on. If you can slip a socket over the plug, that should work for you.

I am sure that lower cowling is removable - the question will be how easy it is, anymore. Worth checking into, though.
Click to expand...

Hey, Lazy - that’s a great idea - c’mon down for some world class bbq, cherry-flavored moonshine and some striper fishin’!

Jes kiddin’ and I am completely BAFFLED as to why I didn’t snap a pic of the physical conundrum (I take pictures of everything when I’m working around the house or engines :)

You know what? I think it is possible to use two fingers to slip a thin deep (very deep) wall socket up into the hole and onto the plug so, the idea of socket the end of which I can use a flat, open end (or perhaps even a ratcheting) wrench may just be the ticket!

Of course, between the fact the spark plugs are at an “upside down angle” AND having used this technique once many moons ago (thinking of trying to get a starter back up into a ‘73 Challenger) I remember double triple care must be taken to avoid cross-threading the new plug when installing it!

Thanks, partner!

(If I get an opportunity to snap a photo I will post it (but, I know now it will quite awhile - have embarked on a big home improvement project and daylight savings time this weekend is gonna KILL my progress :-/
 
Just kidding about that food, drink and fishin'? That sounds awful good!!! :)

Tip for screwing the plug back in and avoiding cross threading... Get a short length of hose that just barely fits snugly over the ceramic. Use the hose to start the plug as it gives you something better to grip onto than just the end of the plug. If it starts to cross thread, the hose will simply spin on the plug.

You're welcome!
 
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Hey, that length of hose idea to get the spark threads started correctly is an awesome one I have got to remember! (And, since I have new plugs on the shelf ready for next year (only 35 hours on the engine thus far) I will be able to find the right inside-diameter hose (or tubing) - THANKS AGAIN!!!

And! I checked with The Admiral and once she found out what you do for a profession, she said, “Tell him to C’mon down!”
Heck, if the grandkids and their parent aren't here (which is like 48 weeks outta the year) the whole upstairs is empty so, Lawd knows, we ... have ... the ... room !!!)

Lake Rhodhiss is a tiny (TINY!) lake in comparison to most but, IT IS QUIET and the fish do get really big!

I tried uploading that pic 3 times (and as a thumbnail) but, for some reason, it will only upload “sideways” (don’t nobody hurt yer neck! :)
 
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That's a very pretty view you have there!

As luck would have it, there's a 150 sitting in the shop right now. I definitely wouldn't go through the hassle of removing that entire mid section cowling. You can definitely get the plug out with normal tools. Whether it's with that plug socket with "flats" on it and open ended wrench (if the socket is long enough)... a short extension and socket wrench... or a plug socket/universal joint/extension/socket wrench... I didn't actually remove a plug, but one look at it and I can tell you that regular tools will get 'er done... and it'll be faster/easier than removing the mid cowling.
 
Roger that!

Will git ‘er dunnnnnn!
(Great feeling to be taking care of the preventative maintenance ourselves. Looking forward to learning more (alternator, thermostat, etc.)

Thanks AGAIN!
 
Lazy Daze said:
As luck would have it, there's a 150 sitting in the shop right now..
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LOL.... Dennis that's funny, since you asked for pics earlier....I have bought a few boats from your store years ago..(I don't think we have met).... So I know you probably had to go up the road to come across the 150. That's awesome you took the time to look at it and help out the OP. You and the team there are top notch...and your participation here sure reflects that...very cool.
 
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You guys are too nice! I certainly don't participate in this forum for accolades - like everyone else, it's simply to help out fellow boaters. But it is a very nice start to my day to read those posts! Thank you.

Blue, just out of curiosity, when was the last time you were at our place? I've been there for 20 years, but I often bounce around between sales, the shop and on-water demos - so I'm not always in the same place all the time.
 
Your dealership is the reason we stopped going to boat shows. I bought a new 2004 240 Sundeck at that years show and the next year bought a 2005 260 Sundancer... Both from Peter. You might remember the fiasco with the trailer for the 260 when one of the wheels caught fire about 10 miles after picking it up. We left Allentown in 2006 for Indianapolis... The 260 kept going and ended up in Lake of the Ozarks.

Is Peter still there I heard he left for a while but I thought I heard he came back?

Anyway you guys always treated me right... And always went above and beyond with any problem. You don't see that very often any more.
 
I do remember!

We don't actually have anyone named "Peter". Peters Marine is a last name, after John Peters, who started the place back in the '30's. But if you're talking about someone that left, it was probably Ted? Was in his upper-30's back then... about 5'8" with sandy hair? Yes, he did leave about 7 years ago - good guy, though - we still keep in touch. Or maybe it was Barry? He was older - and his wife and kids finally convinced him to retire a few years ago :)

I gotta say... it's definitely nice working at a place like this.
 
It was Ted... that’s my wife’s fault. She told me it was Peter. I dealt with Barry too.. nice guy. Glad to hear everyone is doing well.
You’ll remember we ended up getting that monster aluminum trailer for the 260 after the fire. The LOTO guy didn’t want the trailer ... Boatland in Indy wanted it so bad he paid more than you sold it to me for ... good deal
 
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BlueOne, you nailed it! At last count, I am a “community member within” at least thirty (yes, that’s 3-0) forums (LEO, defensive tactics and firearms training; yard care; firearms general-related; shotgun; reloading; classic cars; investing/personal finance, the list goes on).

Club Sea Ray is among my top favorites and it is because of CSR’s knowledgeable , gracious and helpful experts!

(Quite honestly, I know there is NO away the Admiral and I would be where we are in enjoying our boat as much without CSR!!!
 
Blueone said:
It was Ted... that’s my wife’s fault. She told me it was Peter. I dealt with Barry too.. nice guy. Glad to hear everyone is doing well.
You’ll remember we ended up getting that monster aluminum trailer for the 260 after the fire. The LOTO guy didn’t want the trailer ... Boatland in Indy wanted it so bad he paid more than you sold it to me for ... good deal
Click to expand...
That's alright, someone asking for "Peter" happens more often that you'd think :)

Trailer sale... Can't argue with that - Nice!
 
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