Mercury 1500XS: "The Rattle of Death"

Trial by Fire. It was fun until it wasn't. Engine ran great all day. psi was 10psi on the block. I was adjusting the trim to feel the prop slip but lowered it. rpms hit 6300. Used non ethanol fulel with startron and a seafoam. oil mixture was was 50:1 on the heavier side. I dropped the motor 1 inch after the SML testing. A complete tear down is on the menu. Stay tuned! I will figure out where it malfunctioned and rebuild!!! As always, I appreciate you guys watching!!! Leave comments below on what you think was the culprit please!!!! Happy Boating my Friends!!!

[@dennisyoung4631]

*Mercury OUTBOARD Blues!* “I really NEED a Mercury…”

[@BrianJacobsen-cc8sv]

Boys were flying on that boat before it crapped out. Got 70 16' 17' cee bee avenger with 115 l6 video been lifesaver thanks.

[@haroldjuntunen7010]

Very good outboard with a jetpump on it

[@Hausmann300]

She scoots when ya had her on the pin!!!

[@marcouellet1420]

Love your boat i had a 1974 mx 15 with a 115 new in 1974 i just got A VIPER AND A 135 IN LINE AND A SPEED MASTER LOWER I GOT 72MPH BOAT WAS IN A GARAGE 40 YEARS

[@apachebill]

You remind me of me on my little 16’ Bayliner. Just keep trimming and throttling her up till she can’t take anymore. I’ll be whizzing by with my 90 Mercury at 55 MPH and people are just stunned! Cause their big Crown Lines, VIPs and wake boats can’t hang with a little 3 cylinder Bayliner! 😂

[@jimoconnor1275]

Sweet boat but you know what would be really cool?........A second motor......Luv those Merc's

[@loc6880]

What A setUP! From the design of the engine, A "crown" on top of what looked almost like a face on an engine.... The Tail it threw out the back.... And "THE SOUND"!!!! It never gets old...every time you hit that power band and its screaming.... and your rolling.... you can see the grin on your face 😎. There was nothing like those models years....and there never will be... I could watch this for another 30min.... Well done thanks for not keeping it short🤙

[@robertgore8911]

Dang that boat chine walks like a demon! Worked on many of those towers of power back in the day,they love to eat the #3 piston when the timing creeps out of spec.

[@iBackshift]

Uh oh. Ive experienced that sound a few times. Sounds like she' went lean. Still all things considering that squeak, you have a beautiful engine man.

[@felonebike9859]

Man I'll say one thing. That ol gal was shooting a mean rooster tail!

[@gregstaton128]

Rooster tail doesn't mean speed

[@lynn4205]

Depends on which way the roosters going.

[@woofwgn]

Man, sorry you had issues to deal with. With your expertise, you'll be back on the water in no time 👍 When you do find the trouble, it's highly unlikely it had any relation to RPM's IMO. 6300-6500 in a high performance application is the sweet spot on a good 1500. Back in the day when these motors were new, I had friends who ran FJ & SJ class boats ('Family J' V-hull and 'Sport J' tunnel OPC classes). They would always run around 6500 just about wire-to-wire in a 5 mile race. And that was about a 32:1 mix of av gas and good ol' Mercury Oil 😄 Another thing I remember, they believed in the old adage about, "Break it in like you're gonna run it" 🤪 I don't recall any of those guys having problems with seizing or scattering. I have a '73, but I'd love to find a nice '75 J-block someday. I think they look as good as the XS, maybe better with a blue boat. I don't need the LWP. I had two friends who had '77 models where that gearcase tore a strip right down the side of the bullet, front to back. No evidence either one hit anything. They lost it all down there, shaft, gears, bearing carrier, and of course the prop $$$. Amazingly, insurance did cover it. Apparently a weak point 😥

[@robin8559]

That was fun while it lasted. My Merc mechanic said never run any L6 WOT for a long time. Another one had 150 hp for sale and said they go like hell but don't last long. Bummer.

[@D7mSupra]

I hope the 1500xs isnt hurt to bad.. def want to see more of this rig.. my poor viper is on the bck burner

[@D7mSupra]

Hopefully as soon as I get new power packs my new vector will be making an appearance

[@rickcole3768]

Hey Dude-man hope that didnt destroy the motor. When getting on plane, it seems like the motor was too high on the transom. The prop was cavitating a bit before it got a bite on the water. Its possible that when you got up to full speed the water pump got starved. One other thing to address would be the chine walking. Check that your lower motor mounts are not worn...maybe even add solid lower mounts. I noticed it stopped when you added the passenger, thus balancing your load from side to side. Let us know what you find as far as the motor quitting. You were on a roll though! Nice.

[@leerutherford8095]

I could hear it.

[@jasonlamoureux7578]

The way she slowed rpm's before stopping sounded to me like something pulling the reigns.. either gearbox failing or piston halting. Not like throwing a rod or anything, it'll be interesting to see what you find once it's on the bench. Sorry this happened brother, but if anyone can recover the old girl, it is you sir!

[@lynn4205]

# 3 piston was usually the one that seized. Pass poor fuel of the time didn't help either. That's one reason Mercury marine scraped the I Line 6. Use high obtain GOOD fuel no ethanol and 40:1 oil ratio. Might take 2 degrees timing out it WOT timing

[@stevejackson4136]

Can’t wait to finish my Checkmate. Hate that it didn’t hold up. ?

[@panamacitybeachbum]

The thing with these engines... I was always worried my MERC 1500XS would suck a reed valve turning above 6000 rpms. Sold it before I broke it.

[@robertpayton3795]

That's one "whistling unit".

[@MerCSonL6]

Cooking water!!!!

[@45-70SBL]

Just thinking how nice my little 28lb, 3HP Mercury outboard would be in that situation.

[@larslevinberget9558]

Here in Norway it's trending with small kick-up engines on a bracket behind the telescope lantern, the flag and collapsable ladder on the opposite ;P May have to do with 2 generations of faulty 4-stroke engines (in the middle, on an elevated, reinforced transom) or the E10 ethanol causing 2-stroke breakdown ?

[@spitfire27028]

Checkmate? I had an 88 21' Starflight 225 evinrude V-6 hit 72mph. sold the boat 3 seasons ago. never had any chine walk issues though. very nice rid. Im curious to know what you find. sounded to me like putting a chevy in park while driving. well good luck be safe and wear your lanyard at those speeds, great vid

[@G1nn3y]

Too hot? Too lean? Both? As cool as these old 2 stokes are, it does make you start to appreciate modern engine management.

[@MerCSonL6]

None of this above. Son

[@G1nn3y]

@@MerCSonL6 Fair enough. I'm bummed this happened to you.

[@MerCSonL6]

@ginbas cylinder 3 detonated. It's a problem child from what hear.

[@gerardrusso9642]

very curious what happened

[@Kiekhaefer6]

Oh that sucks.

[@keepemlo]

I font do speec but that biat loiks great and ran great

[@rickybrackin543]

Did you build this engine or hours unknown.she was running sweet.

[@jhbuilders]

Hey son. Hope your doing good. Looks like your having fun. Pushin that old merc was like making a 80 year old man do jumping jacks for three hours. Never a good idea.

[@MerCSonL6]

I had a blast. Examined the tapes 50 times at Least. Not a pilot error. Son

[@joshb5576]

That was hard to watch, everything was going well until it stopped. You were really moving, which prop were you spinning this run? Looking forward to the teardown, hoping its nothing catastrophic, though it doesnt sound good!

[@MerCSonL6]

24 pitch chopper

[@afleetcommand]

Sounded awesome until it stopped. Sounded like a seize . Either motor or lower unit right? On my performance saw builds I run 40:1 with an ester based synthetic. The "Semi synthetic" mercury two stroke is "close". I doubt a good oil is going to seize at 6000k, Not unless there was an air leak somewhere to lean it out. But then there would be heat sign. U had too much time on it for it to be piston to wall clearance after a rebuild issue. Did the water stop pumping? And how fast it failed... hoping it was the lower unit seizing . :( Not sure how parts cross from year to year, model to model. Inline 6's up here can be had cheap. I have a 90 and a 115 that could be horse traded for something ( not money ) if u need.

[@Hausmann300]

Glad im not the only one who forgets the ladder😂😂

[@MerCSonL6]

😂

[@andrewcastro2530]

Hello, tough luck: what prop do you use for pulling skiers. What prop were you using to get that speed. I have the 73 Kona ski with 1500 Tower of power.

[@hawgstalkaztv5985]

I have a question for you, I have the mercury 1500 , suppose to be a 150 hp like that but the blue not the red, when i am at WOt and trim up the engine revs real high or even if I do a sharp turn, could it be the engine is too small for my boat ? I have a 1993 skeeter sx200

[@timmaness4749]

Hay buddy what’s the difference between the silver block mid 60s and black block early to mid 70s L6 thanks awesome ride

[@MerCSonL6]

Pistons and porting.

[@lynn4205]

Total different block. Bore and stroke. Late L6 was 99.9 cu in

[@oldschoolriverrat]

Aww man, heartbreaking. I gotta admit though, every time I've heard that motor rev high, I kinda have this uneasy feeling of "how does that thing not blow up?" Well...at least you know how to fix it ;)

[@andrewcastro2530]

Hello, off the subject, what kind of ladder is that on your boat?

[@EricsEpicChannel]

Hi Son, sorry about the motor but I’m sure you will have it running again soon. I was hoping you could help me with an issues I’m having with my 83 mercury 50 4 cylinder. It starts and idles great and but when I give it some throttle it bogs like crazy and doesn’t seem to get above 1800 rpm. I’ve checked the link and sync, been through the carbs several times and I’m getting a nice blue spark that will jump almost an inch gap on every cylinder. It’s definitely not a fuel starvation issue as pumping the primer bulb during the big just makes it worse. If you can think of anything I might be overlooking I would really appreciate it, thanks

[@MerCSonL6]

Flooding? Too much fuel can make it bog down

[@EricsEpicChannel]

Thanks for the reply. I’ve considered it but the floats and idle mixture screws are set to factory spec and as far as I can tell main jets haven’t been swapped either. Have you ever experienced issues with the ignition once the motor warms up? When testing spark I’ve just had it running on the hose for a few minutes

[@Seavoyager45]

Oh No! Mayday, Mayday! I hope its just the fuel pump went out!

[@MerCSonL6]

Fiction can be fun my friend lol

[@geraldkoth654]

I gave up on my L6 1978 115. Gets up on plane and dies seconds later. Two powerheads original 1979 90, all new carburetors, electric fuel pump. Then 1978 115 powerhead, and exactly the same thing. Idles fine, runs fine at low speed, hit the throttle, up on plane about two second later loses power and quits.

[@healthforlife1]

Good morning, I need your expertise..I'm not in a position to hire a mechanic to resolve this issue, so I need to do it myself. I have a 91 xr4 with the single 40amp regulator/rectifier, and I was wondering if you can explain to me what is causing my tacometer not to work but the charging does. From my research, which has been limited in my searching, put the blame on a bad rectifier or stator. If so how do I test those with a dvm

[@MerCSonL6]

Replace the rectifier. Furthermore you can can do a dva test off the 2 yellow wires to ensure that alternating currents are going to the charging system. Son

[@pjimmbojimmbo1990]

The SeaFoam certainly didn't help the engine Those were rated @155hp at the Crank, but I think that rating was about 20hp low. While they were great motors on a Light Hull, they were useless on a heavier Boat.

[@kipwyand7869]

I'll bet you had one of those giant whale tails on your Civic back in the day 😂

[@MF-cq9hs]

Rip tower of power 😢 guess they have rev limiters

[@jamessteed7436]

I need help! to know how to tell what my true rpm is.. and where does it get rpm? Trigger? L6

[@jamessteed7436]

Not a joke😂 says I will run 7 g

[@robertbeasley9942]

mercury L6 the tachometer gets the signal or trigger at the rectifier. the stock tach wire is grey & connected to the stator side of the rectifier. if charge sysrem not working tach wont either. tach should be set on 6 pole. hope that helps

[@robertbeasley9942]

waiting to see what happened ???

[@bassneckfishing2505]

No bro

[@loc6880]

Mercury. Leave you on the water....all the time.

[@MerCSonL6]

Thank you my friend

[@lynn4205]

You need a HOT FOOT throttle pedal and learn how to correct the death wobble in your hull. Learn to keep it on the PAD . Turn steering wheel to left or right to compensate . Start slow yo learn

[@brucegambill6303]

Too bad that boat has a tendency to do the transom walk hull speed scenario

[@user-ru2sx6nx3p]

ARE YOU MAD AT IT......

[@MerCSonL6]

Nope. Non pilot error. #3 burnt down. Son

[@user-ru2sx6nx3p]

@@MerCSonL6 ouch that's MONEY

[@MerCSonL6]

@user-ru2sx6nx3p yea I guess.....

[@lynn4205]

Well I can't find my last text here.but the CDI # for the ign is 114-2986K 1 for distributor and ign. Modual kit. 114- 2986 switch box only. PRO MARINE has these also. My go to store for over 24 yesrs.

[@dalel2220]

You killed the engine. XS engines were meant to be used on tunnel boats. The reason they have low water pickups is for high transom mounting but not high trim. The low water pickup lower unit when over trimmed starves the water intake and overheats the engine. Thats why there is so few of them still around. Dale

[@MerCSonL6]

Thanks. Your wisdom supercedes mine. I've already rebuilt this engine with 150psi on all cylinders. I have 3 J Blocks. How many do you have??????

[@dalel2220]

Dont have any real J blocks but all i mess with is inlines have around 10 from 1000s to 1500s to and a 1250 SBP stacker. They are the coolest motors people love them. I have a video of the stacker running on here under 1250 SBP stacker.. Keep up the good work its getting harder to find them theses days.. Dale

[@lynn4205]

​​@@dalel2220i have a 1000 with a set of Quincy stakes (3) no filler block though. Hard to find. It's on a 15 inch tower. 30, 40 , 44 CU INCH STACKERS FOR mod racing I did in the 70's and 80's( hydros)

[@dalel2220]

@@lynn4205 I didnt have a filler block for mine either but for the mercury pipes you can use the original but just have it milled down to seal.

[@keepemlo]

Noooooooo

[@321CatboxWA]

Too many RPM . 5,500 max .

[@MerCSonL6]

Really?? Ok.....

[@dalel2220]

I run my 1350 stacker at 6200 no problem Run 25 to 1 oil and good water pump. Dale

[@larslevinberget9558]

Dude, that Merc didn't sound healthy at all. First, she's so old she would need 2 or even 3 % oil in the 98 octane fuel Second, it should have more water cooling, as you have hyped the tilt so much, she's squirting like a teenage girl :D

[@MerCSonL6]

Haha. Agree my friend. Son

[@vandos11]

Too many Rs dude

[@MerCSonL6]

Nah. Conrad hit 7K with no issues. Son

[@vandos11]

@@MerCSonL6 just unsubscribed SON

[@MerCSonL6]

@@vandos11 Thank you so much!!!! I appreciate that!!!

[@lynn4205]

😅