Evinrude 50hp powerhead removal problem

evinrude model 507125s

I removed the nuts as noted by A & B in the photo, removed the 4 motor mount bolts and all other misc, wires, controls. Flywheel is off. used block and tackel with a good bit of tension on powerhead and rocked it back and forth with only a very minor amount of movement noted in the powerhead studs, powerhead will not break free,

am I missing a bolt somewhere like at the front half of the casing under the carbs pointing towards the rear of the block or do i just need to keep rocking the powerhead until it free's itself?




A. 8 nuts for powerhead studs on port and stb. side
B. 1 nut at rear of powerhead
C. did not remove 2 bolts (told these are for exhaust housing)

D. appears to be a pin in the attached photo or is there a bolt, nut up front ?

Joe

Re: Evinrude 50hp powerhead removal problem

did you drop the lower unit, make it much easier.

Re: Evinrude 50hp powerhead removal problem

its possible that the driveshaft splines are seized to the crank.

Re: Evinrude 50hp powerhead removal problem

tashasdaddy, petryshyn

thanks for the quick replies,

tashasdaddy: did you drop the lower unit

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removed all bolts (4 port & stb side and 3 from under cavitation plate) and Lower Unit housing wobbles freelyand has about 1/16" seperation. The L Unit will not drop! Rocked Unit left, right, side to side, pulled down, pushed up while rocking, Unit will not give. Rolled a cigarette, drank a cup of coffee while mumering at it, tried re-rocking, pulling pushing and rotated flywheel in small increments , again & again with no avail. Mummered at it a bit more ...

petryshyn: its possible that the driveshaft splines are seized to the crank

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it seems to be!, whats a fix? flip it upside down, flood the shaft with wd40 and "hope" it migrates to the splines? or drink more coffe while mummering at ti.

Re: Evinrude 50hp powerhead removal problem

not pretty,you have all the bolts out,your problem is the stuck driveshaft,if you force the powerhead too much,you will break the bottom of the crank,also,there are set pins that are used for placement of the powerhead,so it wont rotate,chances of getting the shaft out by spraying wd40 is low,you might be able to use wooden wedges to seperatethe lower,when engines run,we have had the ability to remove all bolts and fire it up,we sometimes got the shaft to vibrat out,a successful way i have done it when it didnt run was, using your picture,the area with the 'a' we used a large hole saw ,like 11/2 or larger,drill a plug out in the area that allows contact with driveshaft,after the plug is removed,take a dull air chistle,gringd it dull and give it a bit of a concave grind to allw to hold to the driveshaft,give vibration to the driveshaft spinning it,putting pressure on/off the seperation at the lowerunit.if you have no luck,then its cut the shaft and replace it,after the powerhead is removed,if the crank was cut,I used a couple weights from a barbell set,slide them on shaft and lock on a few pairs of vicegrips/or weld a washer to shaft and use the weights for a puller,rem,ember to save the alum plug to weld back,be absolutly certain the splines in the crank are not rusted to the point that ,first time the prop hits ,they strip.Im embarrased to tell you it happened to me on my 235 yrs ago.Rebuilt the whole deal,one of the first outings I bumped bottom here in the Keys ,which happens alot,engine went into sudden neutral at a high rpm with the heat horn going off in seconds.That ALL said.Is your eng.worth all the trouble??for a rebuild.Good Luck

Re: Evinrude 50hp powerhead removal problem

Mike,
your input is very much appreciated, I will put the boat on its lift with forty or so lbs (Weights) hanging from the lower unit with a strap and back out the lower unit securing bolts about 1/4 inch with hopes that while running the vibrations will loosen the shaft from the crank and drop a bit. With luck I will have a starting point to continue with lower unit removal. Will post an update when I get around to doing someting.

Is your eng.worth all the trouble??for a rebuild.

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won't know unless i can split the casing.

1962 Larson Playboy runabout


Boat, motor & trailer cost me $450. I put about 300 gallons of fuel into it this summer, if not more. The motor is now starting to get a bit noisey and winter will be here shortly in northern Minnesota, so i will have plenty of indoor time to dink around until next boating season.

THIS MOTORS STORY: prop seems to be about 30+ yrs old and it likely has at least 1/4" worn from its leading edges aside from being pitted. Did I know when running short burst on occassion at WOT that the engine was exceeding 5500 rpm's, YES! - the engine sound was obvious of that. Did I load up the engine by doing power turns on occassion, YES!

Forceing an elderly person that needs a walking stick for stability to run down hill would be not much different than what I did to this motor.

As I mummer at the motor during this teardown, am i in reality mummering at myself for being such an arse! - YESSSSS!

Re: Evinrude 50hp powerhead removal problem

The part in your photo that is red, is the exhaust housing adapter. The powerhead is held to it by the bolts that you pulled in a downward direction. In addition to these fasteners, there is also a stud in the back of the powerhead that goes down into the adapter, when you fit the powerhead to it. The stud passes through the adapter and is fastened in place with a nut. That nut is located just forward of the area that you have marked as "C." When the lower cowl is in place, it is accessible from within the cowl.

If you have not removed the nut on this stud, the powerhead is not going to separate from the exhaust housing and adapter. If you have, the problem in regarding to removing it, is obviously related to whatever is going on with your attempt to drop the gear case.



.

Re: Evinrude 50hp powerhead removal problem

Nobody mentioned shift linkage.

It's a thought

Re: Evinrude 50hp powerhead removal problem

I was wondering that too^^^

Re: Evinrude 50hp powerhead removal problem

jay_merrill: there is also a stud in the back of the powerhead that

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thanks Jay, 1st photo of thread i got off of the net, photo below is rear of my engine,

Photo: rear powerhead stud through exhaust adapter (nut removed)

Les Robb: Nobody mentioned shift linkage

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linkage, hydroshift wireing is noted in 1st photo (solenoid wires)

Re: Evinrude 50hp powerhead removal problem

some will shoot me for saying this but here goes see the stud in the middle pointing down from the powerhead get a flat head screw driver a large screw driver so u have some leverage and slowly but gently push the stud up sometimes it can become stuck with salt if the engine has been used in salt water also when u have tried lifting the powerhead off are u sure your lifting it vertical with the rest of the engine? if your slightly off that stud wont allow the power head to lift at the rear altho u will get the front of the powerhead to lift up a little

Re: Evinrude 50hp powerhead removal problem

gazza2007au: are u sure your lifting it vertical with the rest of the engine

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good point, yes pull on the crank is inline, visually checked vertical pull from side to side & front to back for alignment after initial force was applied with block and tackle. At this point I need to get the lower unit to drop.


my intent is something along the line in this photo, loosen lower unit securing bolts about 1/4", hang weight from lower unit, run engine at idle, rock the lower unit around in forward, reverse and neutral with hopes vibrations will loosen shaft siezed splines? to drop from the crank.

Photo: Weights hanging on lower unit with 1/4" clearance above a plywood square that is under weights:


I left this ol oak tree up because it had 1 last green limb, got rid of the rest since it was to close to the house, hollow and full of Bats!

Viva La Shady Tree Mechanics!

Re: Evinrude 50hp powerhead removal problem

be real careful as u might pull the shaft from the gearbox yes ive seen it done and i stupidly enough brought the motor not knowing so if u do that not only will u need a new crank but a gearbox as well try taking out all of the bolts instead of just loosening them

Re: Evinrude 50hp powerhead removal problem

please comment to this post on what you see/observe in

• the crank closeup photo
• spark plug photo
  plug tips are highlighted from flash, not white as in photo,
  shinney right now, but not white yet!

my intent at this point with this motor is to slap a set of connecting rod bearings
for very gentle putt putting over the next month to enjoy the fall colors up and down our backyard lake channel.

update on freeing driveshaft from crank:

(no success)
ran engine at idle , neutral, forward & reverse while working lower unit
with hopes vibrations would free shaft from crank.
(used 25#'s of weight strapped to lower unit)

(no success)
removed, carbs, electronics/ignition & all other misc. put flywheel back on
and strapped vibrating sander to top of flywheel with heavy duty bungy
cords with hopes while working lower lower unit harmonics/vibrations would
free shaft from crank.
(used 25#'s of weight strapped to lower unit)

unable to drop lower unit: no water impeller replacement if ever needed,
thank goodness for now it is working great. (knock on wood)


Dr. SawBone Takes a Pot Shot
split lower cover with hacksaw to gain access to the 2 crankcase head
screws that bolt up to front casing half.



Backed out crankcase head screws until they butted against steering arm
and severed them with hacksaw. (replacement bolts will need just under 1/4"
cut off to re-insert)

• casing half's appears to have no seal from previous rebuild
  (residual oil film where casing halfs join, from oil blowing out of casing?)
• bearings fairly dry
• connecting rod bearings very loose (lower more so than upper)
• lower connecting rod cap (bluish in tint - from heating up?)
• lower crankcase head o-ring broken (surface rust deposits)
  it has a 1/16" gap where the casing half's join, not visible in photo

large Crank Image , 1380x960





Plugs:


plug tips are highlighted from flash, not white as in photo,
shinney right now, but not white yet!

compression at 125 +/- 10psi both cylinders

Re: Evinrude 50hp powerhead removal problem

I must say,that is a first for me.You are quite willing to take upon a challange.Did you have water hooked up to your lowerunit when you ran the eng.Because if not,you likely distroyed the impeller.At this point,you can continue with one more option at puling the driveshaft.That would require you to heat the lower crankshaft end in hopes to expand it enough to free up the trapped splines,r the original plan I mentioned about drilling out a plug with a hole saw allowing access to cut the driveshaft,then replace the driveshaft,or if you have a great machinist weld it back,if you choose to heat the lower crank,you will distroy the bottom seals,which Id bet are bad already.Is that rust on the sparkplugs,if so you may be pulling water thru the bottom end already.I need ask,why are you doing all this,you say you wanted to sneak in some rod berings,proceed by pulling the rod caps off,you probably have a bad crank at this point as well,I hate to say it ,but your not going to have success with half measures .It also looks as though that was a rebuilt or a factory replacement powerhead ,based on the red color

Re: Evinrude 50hp powerhead removal problem

mikesea: You are quite willing to take upon a challange..........Did you have water hooked up to your lowerunit

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Note: I do not trust any mechinism that can spin when a motor is running nor do i trust any electrical or mechanical linkage when a motor is running

i was advised not to run this make and model with a boot, something about water flow being insufficient that a tank is best for test. I used 1" rope tied around lower unit with a 1 foot pigtail and ran motor for short periods with water boot, 2-3 minutes at idle and rocked lower lower unit side to side. Held rope at end of pigtail to not give it a chance of wrapping around my hand.

Plugs, are brown in color, no rust, I noticed the top plug outter ring has more carbon than the lower, the lower seems to have cleaned itself off from heat (lean?), top plug has a bit of black still on the porcelean whereas the lower has practically nill. The crank and bearings were fairly dry when i opened up the casing and the lower connecting rod cap had a bluish tint to it. It's as if the engine lost lubrication, water pump is strong and head temp while runnig is ok to the touch. No scoring of the cylinder walls, no metal noted anywhere (like metal bits of fried bearing cages).

Good News, today i dounced all main and piston bearings with oil, pumped wd40 through the bearing oil holes and then re-oiled all again. I pumped a heck of a lot of wd and oil into that lower roller bearing. while engine was lying on the ground I worked the bearing around quite a bit with the flywheel and then worked the bearings some more after I hung the motor back on the hull.

Re-assembled the rest of the motor, carb, ignition, steering, controls and when I started to tighten up the lower unit I noticed seperation between the powerhead and exhaust adapter.

For cripes sakes!, at that point I was 30 minutes from taking an evening putt putt down the channnel to enjoy the fall foilage. So ....... off I went putt putting.

I will continue to putt putt until the boating season is over and pull the powerhead then for an overall inspection. I still have to replace the 2 bolts i severed from the crank head.

Geesh! for now, First Rule of Rum is .... putt, putt, putt ....

Re: Evinrude 50hp powerhead removal problem

Congratulations on sticking with it. I don't think my patience would have lasted. Keep us posted in the future, but for what it's worth department I think I would consider a new short block if one is available.

Based on the pic's you are probably to the point of cutting the lower part of crank shaft with slits (4/12" angle grinder with thin metal cutting blade), and then gently split it with a cold chisel. At least you'll know why you couldn't seperate the two. Worst case the lower unit drive shaft if worn and stuck in between grooves. Best is the crank shaft worn and no damage to drive shaft.

Final thought, dunk bottom of lower unit in ice water and heat the crank shaft with acetalene torch. Make sure drive shaft dosen't heat up over ambient temperature. (Don't need to rebuild it too)

Again best of luck

Re: Evinrude 50hp powerhead removal problem

again,I say,I amazed,I have to print your persistance out and show it to a few quitters.Im admitting right now.I never thought you would get her running again,and to do all that out of the norm stuff,my hats off to ya.PUT PUTT my friend.

Re: Evinrude 50hp powerhead removal problem

mikesea: .... my hats off to ya.PUT PUTT my friend

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Well I have to admit, I have wound it up to the 4000rpm range a few times
and she sounds great ... the lower cowl bolted back and is prety darn stable.



jb weld pushed from the inside out and wiped smooth on the outside
will likely hold and match color.

Re: Evinrude 50hp powerhead removal problem

I think I would have broken out the smoke wrench a long time ago.

Good Job.