2.4L top bearing spun.

[chester8420]

I have a 2.4L 200 that was rebuilt about 50 hours ago. Tuesday, I was running it on Flint River. I had it around 6400 RPM for a minute or so, then I slowed down and went under a bridge at idle. On the other side, I punched it and had just got up to about to 55mph when it lost power. I had just went past the boat ramp, so I turned around to head back. I got the boat turned around, but it made some metallic noises and quit.

I got it out of the water and pulled the heads. The top 2 cylinders had steel debris embedded in the top of the pistons, but otherwise the pistons and cylinder walls looked ok. I was turning the engine over by hand with the flywheel, and I noticed the flywheel was hitting the trigger/stator. I can wiggle the flywheel around, so it seems the top bearing let loose.

What do you folks think caused this, and what can I do to prevent it again? I haven't torn it down yet, so I don't know what shape the crank/block is in. Regardless, my first baby is due in 3 weeks, so it looks like I will be without a boat this summer.:(

I have had a lot of trouble out of this motor in the past, but it has been running good since the rebuild last winter. The last mechanical failure occured when a ring caught a port and broke a ring land and chewed up a piston. The previous owner had a steel sleeve put in and they did not chamfer the edges of the ports on that cylinder.

Any advice would be greatly appreciated. Should I ditch this 2.4 and try something different? (when I can save up some money...)

[ChrisCarsonMarine]

The 2.4 is a good engine platform,yours will need to come apart to see what's left.Youre going to need a crank,and a couple pistons and a full set of rings,at least...open it up and see what's up.Theres a good chance the bearing failed from lack of oil... Plugged one-way valve at the bottom front of the crankcase.We always use clear tygon tubing so there's a visual check for oil moving from top to bottom,this has saved a lit of motors,Chris

[Billy C]

If you can wiggle the flywheel as you said.it sounds like a broken crankshaft.

[chester8420]

Thanks for the advice Mr. Carson and Billy. I'll get it tore down in the next few days and I'll see what we got. I'll check the one way valve, and see what we got on the crankshaft. It turns contiguous by hand, but I suppose it could be broken, and just lined back up at the moment... Thanks guys! -Chris

[kingsbiship]

I broke a crankshaft once and it was similar to what you're saying! A bad or spun bearing wouldn't let you rock the flywheel
like that cause there are 3 others holding the crank! And they don't snap straight across so you will still be able to spin the
engine over. I drove home on 4 cylinders.

[King Dad]

Keep in mind.. that a 2.4 litre Merc, when assembling, must have the upper main bearing assembly instaled on the crank when you install the front have of the crankcase. If you install the front half, tighten the bolts and then attempt to "draw" the bearing assembly/upper main assembly into/onto the crank using the 4 bolts, you'll damage it .It's just too tight a fit! Been there, done it!!! Rebuilt crank!!!! (mine lasted about 20 hrs before it let loose.The OMC engines you can do it that way and I've done it zilions of times, but not Merc. AND, I almost always feed oil via the lower main-to-upper-main by-pass hose each time I use it. I am over cautious about oiling it now. I don't want to rebuild it anymore. Some parts are getting impossible to find... and afford!! Next motor will be 2.5 litre, for sure!!

[luckybuff]

Keep in mind.. that a 2.4 litre Merc, when assembling, must have the upper main bearing assembly instaled on the crank when you install the front have of the crankcase. If you install the front half, tighten the bolts and then attempt to "draw" the bearing assembly/upper main assembly into/onto the crank using the 4 bolts, you'll damage it .It's just too tight a fit! Been there, done it!!! Rebuilt crank!!!! (mine lasted about 20 hrs before it let loose.The OMC engines you can do it that way and I've done it zilions of times, but not Merc. AND, I almost always feed oil via the lower main-to-upper-main by-pass hose each time I use it. I am over cautious about oiling it now. I don't want to rebuild it anymore. Some parts are getting impossible to find... and afford!! Next motor will be 2.5 litre, for sure!!

On Chris comment on tygon line use and flow, I understand he says the flow direction is from top to bottom?

[luckybuff]

And does a 2.5L require the same top to bottom flow?

[luckybuff]

Found a post from "moldman". Flows and checks fuel/mix going up to the top. Just wana b sure, I have a 2.5L I will be testing soon.

[johnnyracer]

Bottom to top guys. with at least one check valve and sometimes 2. If only one its usually on the bottom.

[King Dad]

The "puddleing" of fuel/oil is the concern. By virture of gravity, it puddles towards the bottom of things; the crankcase, just behind the reeds, past the crankcase seals, etc. So, you re-direct that well over-rich "soup" back up towards the top of the engine, where it can either be used again or puddle somewhere else.. again.

[luckybuff]

The "puddleing" of fuel/oil is the concern. By virture of gravity, it puddles towards the bottom of things; the crankcase, just behind the reeds, past the crankcase seals, etc. So, you re-direct that well over-rich "soup" back up towards the top of the engine, where it can either be used again or puddle somewhere else.. again.

Sound logical! Like when we drink sour milk or way too much beer. :)

luckybuff

[Quinten]

Interesting, when I recently had my reed block adapter off, the manual said check for tightness and operation of my one way check valve/s. I looked all over the intake and couldn't find it. Sounds like it was on the front half of the block? It didn't mention that and I didn't look there either. Sorry for the high jack. Sounds like I need to find and check mine, then get some of the hose Chris mentioned. Anything I can do to keep the old girl running.

[ChrisCarsonMarine]

The 2.4 is a good engine platform,yours will need to come apart to see what's left.Youre going to need a crank,and a couple pistons and a full set of rings,at least...open it up and see what's up.Theres a good chance the bearing failed from lack of oil... Plugged one-way valve at the bottom front of the crankcase.We always use clear tygon tubing so there's a visual check for oil moving from top to bottom,this has saved a lit of motors,Chris
Being sick and overloaded has made me delirious...the residual oil that finds its way to the bottom main area is pushed by crankcase pulses through a one way valve at the bottom front of the crankcase through an oil line to the barb(no valve) on the top front of the crankcase to lube the top main bearing.The oil path is Definately from BOTTOM to TOP,Sorry for my earlier confusion,Chris

[chester8420]

Thanks for all the good info guys! I just rebuilt the engine last winter, it is a shame that it only lasted this long. I really want to get it right this time!

[timmc6]

Thanks for all the good info guys! I just rebuilt the engine last winter, it is a shame that it only lasted this long. I really want to get it right this time!
i see you are in dooly county,do you know tim cremons in albany, i dont know the the name of his business but he knows his stuff,!!!!!!!!!!!tim:cheers: he his a old mov vp racer,engine builder!!!!!!!!!!!!

[dagodiver]

The 2.4 is a good engine platform,yours will need to come apart to see what's left.Youre going to need a crank,and a couple pistons and a full set of rings,at least...open it up and see what's up.Theres a good chance the bearing failed from lack of oil... Plugged one-way valve at the bottom front of the crankcase.We always use clear tygon tubing so there's a visual check for oil moving from top to bottom,this has saved a lit of motors,Chris

pictures of this valve and hose.? I am running a 2.4 and want to check.
thanks.

Dago.

[chester8420]

i see you are in dooly county,do you know tim cremons in albany, i dont know the the name of his business but he knows his stuff,!!!!!!!!!!!tim:cheers: he his a old mov vp racer,engine builder!!!!!!!!!!!!
I do not know Tim Cremons. Kinda ironic though that my buddy that rebuilt my motor with me is Tim Parker. He works on boats on the side, and has a pile of spare 2.4L parts. He really helped me out with the last rebuild.

Just too many Tim(s) around!

After all the trouble I've had out of this motor I'm starting to get a bad taste in my mouth for V6 mercs. I suppose I shoud start over because this motor has been blown up, welded up, bored, sleeved, re-bored, and generally beat on since 1983. :rolleyes: I just keep hoping I've got it fixed, so I can go fishing a few times. It got me through last year at least.

In all fairness to the motor, it has spent quite a few hours in the 6400-6500RPM range. :thumbsup:

[timmc6]

I do not know Tim Cremons. Kinda ironic though that my buddy that rebuilt my motor with me is Tim Parker. He works on boats on the side, and has a pile of spare 2.4L parts. He really helped me out with the last rebuild.

Just too many Tim(s) around!

After all the trouble I've had out of this motor I'm starting to get a bad taste in my mouth for V6 mercs. I suppose I shoud start over because this motor has been blown up, welded up, bored, sleeved, re-bored, and generally beat on since 1983. :rolleyes: I just keep hoping I've got it fixed, so I can go fishing a few times. It got me through last year at least.

In all fairness to the motor, it has spent quite a few hours in the 6400-6500RPM range. :thumbsup:

tim cremmons owns a machine shop in albany he builds drag racing motors and he is top notch,he can weld and turn outboard cranks if he wants to,good guy ,tim

[chester8420]

I just found out from my buddy that Tim Crimmins owns HI-TEC in Albany. I knew that name sounded familiar! I've been to his shop before. He is the guy that bored my 2.4L block after it blew the first time...

[chester8420]

Well I know this is a 4 month old thread, but I just now got the motor torn down. (My wife and I just had our first child in May... Nuff said)

If you can wiggle the flywheel as you said.it sounds like a broken crankshaft.

I broke a crankshaft once and it was similar to what you're saying!
Well you guys guessed it. The crank broke between the upper 2 cylinders and the center 2 cylinders. The sealing rings around the break are shredded and the crank bearing nearest the break is also destroyed.

http://i48.photobucket.com/albums/f230/chester8420/0817132023_zps9e89ce3c.jpg (http://s48.photobucket.com/user/chester8420/media/0817132023_zps9e89ce3c.jpg.html)

http://i48.photobucket.com/albums/f230/chester8420/0817132023a_zpsfd38671c.jpg (http://s48.photobucket.com/user/chester8420/media/0817132023a_zpsfd38671c.jpg.html)

I have another powerhead with a good crank. I was gonna slap it in and go fishing, but the block and front half have damage where the seal ring rides. It appears as if the crank rode around on the seal ring ridge a few thousand times when the crank broke. What do you folks recommend as a fix? Is there any chance I can clean up the seal ring ridge, and hope the seal rings on the new crank make good enough contact? Or can I JB weld the seal ring to the seal ring ridge? Can I make do without a seal ring there?

My budget for this repair is $0. That's why I'm suggesting rigging it somehow instead of buying a new block and front half, like I ought to.

[Capt.Insane-o]

meh, that thing is toasted.

[chester8420]

meh, that thing is toasted.Yeah. But I keep bringing it back from the dead! haha

You should take a look at the lower unit! The last time I had it apart, I had to pull the bearing carrier with a pulley puller and beat the carrier back into the torpedo with a piece of pipe and a sledge hammer.

I would love to ditch the carb'd 2.4 and get going fresh with a good efi 2.5.

[chester8420]

I got it patched back together last week with jb weld and a grinder. Little copper coat and a melted stator... Took it out for a test run. It ran great for about 10 minutes, then motor just shut off. I got back to dock and found out that the top bearing cap's stator mount broke off.

I guess I shouldn't have re-used the top cap after the crank broke and the flywheel beat the stator screws out of the cast aluminum and broke the little guide ring.... I drilled and tapped the top cap's stator screw holes for 1/4 bolts, but I guess I didn't get the holes exactly right and the flywheel hit the stator again. Gotta love it.

I need a top cap, bearing, stator and trigger for a 2.4 200. Will a 2.5L top cap fit?

[johnboy 88 vegas]

After all the trouble I've had out of this motor I'm starting to get a bad taste in my mouth for V6 mercs. I suppose I shoud start over because this motor has been blown up, welded up, bored, sleeved, re-bored, and generally beat on since 1983. :rolleyes: I just keep hoping I've got it fixed, so I can go fishing a few times. It got me through last year at least.

In all fairness to the motor, it has spent quite a few hours in the 6400-6500RPM range. :thumbsup:


Sorry bout your sour luck but quite frankly I have the best luck with old raggedy junk...well besides my 2 liter spittin a ring on the water hose...instead of at 6800 bout 20 minutes before that. If ya want it to tear up it never will but heaven forbid you put good money into a motor and boom when least expect it. First V6 Merc I tore up just got done with a 2 mile 7k rpm run and was cruising at 4k for about 30 seconds before a rod sawzalled the block in half. I would have felt a lot better if this happened at 7k instead of 4k but thats just my luck. Lesson learned....don't let off the pedal or it might tear up..LOL!!!

[chester8420]

I would have felt a lot better if this happened at 7k instead of 4k but thats just my luck. Lesson learned....don't let off the pedal or it might tear up..LOL!!! I hear ya! I was a few minutes into the test run.. The motor was running good, about and I was just about to open it up, and I decided to play it safe and head back towards the dock. It broke as I was turning around at about 3,500rpm. lame.

[bobthebuilder]

Buy an old rotted out boat somewhere with a 2.4 on it with OK compression and you can use a lot of your old parts on it also.. I used to do that several years ago... I bought one I remember for 400 bucks with a good motor on it... That is after freshening it up a bit.. Only ay to do it with a near 0 budget. but I have done it before and I believe it can still be done.

[johnboy 88 vegas]

Paid 600 bucks for my 2 liter and probably have 200 in parts....been the funnest motor I've ever owned cause I don't give three craps if it tears up tomorrow.

[chester8420]

Well, I found out what went wrong. I used my old top cap with the donor crank. The donor crank requires a 1.35inch top bearing diameter. My old crank had a 1.5inch diameter bearing. That didn't work for long.

I did not know that some of the older 2.4's had a larger dia. upper crank bearing. Gotta love it.

[bobthebuilder]

Yea, the 1 1/2 top bearing journals we sometimes --I should say most of the time we get them turned down by a local automotive shop here to 1.375... The smaller size uses larger rollers and seems to do much better. I just told a friend about an old Ranger bass boat and he went and bought it for 900 bucks.. The boat turned out to be OK just needs some cleaning up and some TLC.. He can sell the boat and trailer and trolling motor for 900 I am sure.. It isn't a bad looking thing. He got a 2.4 200 Merc on it that runs OK.. He is bringing it to my shop next week for me to do carbs and fuel system clean up --water pump--therms-- and so on.. It makes for a low dollar engine that's OK.. You need to do one of them.. They are not there every day but keep your eye on Craig's List... one will come!