Abby's Guide to Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more)
Username Password
Discussions Reviews More Guides
Abby’s Guide > Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) > Discussions > Small engine repair questions, Tecumseh HSSK50

Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Discussions

Search For:
trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Small engine repair questions, Tecumseh HSSK50
Original Message   May 19, 2008 9:37 pm

Iíve got a few questions on rebuilding a small engine.The engine is a Tecumseh HSSK50 67366S.†† I think the model year is 1998.It came off an MTD Gold 526 snowblower and had a broken rod.The exploded parts view is here:

http://www.outdoordistributors.com/pdf/Tecumseh/TECUMSEH-MODEL-HSSK50-67366S-PARTS-LIST.pdf

†† Iím just experimenting to see whatís involved with doing some repair on engines and this engine was broken and free so a good candidate.If I mess it up in learning it wonít be much of a loss.

Question 1:

After taking off the head I tried to move the piston back and forth with my fingers.It seemed tight and did not move from side to side.The reading Iíve done says to measure the space at the wall.I assume they meant the ring to wall distance and not the piston to wall distance.

††† They mentioned taking a reading of the gap but did not say how to do that.How do you take a measurement of that distance? You canít use thin flat sparkplug feelers as theyíre too stiff to bend with the wall shape.They would press out so not give an accurate feel.How do you measure the ring to wall gap?

Question 2:

†† What are acceptable limits for the gap?

Question 3.

†† I donít have a dial gauge that can take an inside reading of the cylinder.I have dial calipers but I donít think they would be accurate enough.There may or may not be a ridge at the top of the wall so the calipers would read the ridge and not be able to get deeper.Is there a way around this without having a special gauge for taking the reading?

Question 4:

†† Given that I donít have gauges for an inside wall measure would it be unreasonable to assume a 10 year old motor would be worn and just put in .010 oversized rings?Lightly hone out the cylinder wall and go with .010 rings?

†† Just say the motor was lightly used and the wall in excellent shape.Would putting in .010 rings cause problems by being too tight?

Question 5.

†† On opening up the case I looked for timing marks.I think one is a hole in the cam gear.I did not move anything before taking out the crank and cam.I could not find another mark on the crank gear to mate with the hole in the cam gear.

†† I should have made some scratches but did not for some reason.I think I got a phone call and forgot when I got back.Does anyone know the marks on this engine?My reading said to look for a raised dash or one of the teeth on the crank gear to be beveled.I could not find either or any other mark.How can I get the alignment right?I could put it back together with the case open and hand turn the crank and watch the valves but I think I might be off a tooth or two doing it that way. ??

Question 6:

††The crank journal (the place where the piston gets bolted to the crankshaft) looks shiny and without scratches.The piston and rings look undamaged.The valves and tappets look fine.There is no place inside that seems to have gotten hit by the broken rod end or the broken bottom part.The only place that got scratched was on the crank.That was big bulging part I think is a counter weight for the crank.It got scrapped quite a bit over a few inches but I donít think thereís been enough metal removed to make a difference in weight so seems like that damage would not factor in.

†† Given that all the parts seem ok if I were to bypass putting in rings the minimum repair would be putting in a new rod and at least cleaning and lapping the valves.The minimum job would be doing that and putting everything back in and torque what ever needs to be touqued.Does that sound right?

trouts

Replies: 6 - 15 of 25Next page of topicsPreviousNextNext page of topicsAllView as Outline
trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Re: Small engine repair questions, Tecumseh HSSK50
Reply #6   May 21, 2008 6:32 pm

†† Thanks for mentioning the epoxy.I just might do that.The engine looks-wise is in excellent shape.Thereís no rust rash around the head bolts and the cowling and recoil look new.I looked pretty close at the insides and I think the damage is only in that one spot.

†† The other 5hp was taken apart today.It also had a broken rod.The case on that one looks intact.Thereís one gouged spot but no sign of puffing out the case or cracks.The crank journal on this one is all chewed up and the piston skirt off in chunks.From what Iíve seen so far the case should be salvageable but would require at a minimum rings, piston and rod.†† I just finished up taking it apart so tomorrow will do the refined cleaning and take a better look at everything.

†† I compared the piston on both 5hpís, the newer 5 versus the older 5.The new 5 had a larger diameter piston.Its rings were not as thick.Its piston skirt was not very†long and the bottom cut parallel to the piston top surface.The older piston had the skirt extend down past where the new one was cut off as in an extended v in two places.The cross pin that holds the rod was smaller than the older pin and on the new piston inset into the side diameter so less metal in the pin and less in the piston body.

††† So the newer piston was larger diameter but less overall metal so lighter.

††† The cranks were also different.Iíll try to post a picture.The newer one was shorter and lighter.The cam gear was much smaller on the new 5 and the counter weights also much smaller.

††† Given all that extra weight rotating at 3600 rpm thereís got to be more torque in the older motor.

†††† The older 5hp came on a Jacobson Imperial 526 which is an odd size these days.It might be nice to get this one working again.The engineers should have sized a motor capable of good performance so I expect this engine if in good shape might toss snow well.

†† The body paint is all gone and the machine completely covered in surface rust but the metal all solid.The tractor insides are unworn and tight.The friction disk looks new and unused.Itís wider than any Iíve ever seen and thicker than either Ariens or Toro rubber from the 70ís.The scraper bar seems original and without wear.It would be nice to see this thing run so maybe Iíll give this motor a shot if thereís nothing else wrong with the motor.

††††The cams were compared and the cam from the older 5hp is significantly heavier than the newer 5hp crank.

††† The engines are covered with dirt and oil so pretty messy and not so easy to clean.††Below is†the poor man's cleaning tank made up this morning for cleaning the 5hp.† It's a 5 gallon plastic gas can with the top cut out as a splash shield.† Put the parts inside which get cleaned with gas and a paint brush.† When done the gas is poured back into a spare 1 gallon gas can†for reuse later.† The dirt and grime left on the bottom is cleaned out with a rag.† It worked out pretty well.† The parts get clean with only a film of oil and gas which cleans off easily with warm water and soap.

trouts2
This message was modified May 22, 2008 by trouts2
friiy


Location: Las Vegas, The Desert
Joined: Apr 12, 2008
Points: 600

Re: Small engine repair questions, Tecumseh HSSK50
Reply #7   May 23, 2008 12:13 pm
Hey Trouts2,

The epoxy I was talking about is 1838 b/a green by Scotch-weld...good stuff..

Your 7 hp that blows oil from the breather may have a problem with the ring gap.

I have seen rings that spun in their groove and lined up with each other,† meaning that compression and exhaust blowby is maximized,† or you may have a compression ring that has stuck (carboned or seized ) in the groove compressed (making it in-effective)

OR... you may have a breather assy. that the reed valve is loose or stuck part open.† (try swapping with another breather assy.)

If you need piston/ ring assy. on a TEC. motor.†† I like to use the aftermarket company Rotory Corp.† for those kits.†† they made taking in older engines that need rings more cost effective for repair.

Good Luck,

Friiy

trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Re: Small engine repair questions, Tecumseh HSSK50
Reply #8   May 24, 2008 10:10 pm

Friiy,

†† I donít want to trouble you with mailing the epoxy.††† I located several places that sell 1838 but their lowest quantity is one ďkitĒ composed of 6 kits of 6 sets of epoxy and hardener.I will eventually use up 6 sets but not 6 kits of 6 sets.One place is checking to see if they can send one ďkitĒ of 6 sets and will get back to me on Monday.Iíll probably give the 5hp with the cracked case a shot.

††† The Rotary companyrequires an account before theyíll give me a login so Iíll get in touch with them on Monday.

††† The second 5hp is out of the running for a scored crank, broken piston and rod.

†† Today I opened the7hp and itís looking good.It gushed oil so the parts are good.The opening went a little smoother so I recorded the positions of the crank, cam and rod retainer and took pictures.The push rods were taped and marked with their positions.

The ring alignment was ok I think.The top ring gap was at about 7-8 oíclock, the second ring at 3 oíclock and the oil ring at 5 oíclock.††

†† The breather is confusing.When I check the breathers on engines I look for the round cover to move in and return to the cover plate.Iíve never had one stuck or not return to the plate but I never know if itís sealing 100% or not.Is it that critical to have 100% seal?Is it internal pressure that closes it?Anyway the ones Iíve checked in the past seemed to be closing and without obstructions preventing full closing and itís like that on this 7hp.

†† The rings moved freely in their groves so ok, no carbon caused sticking.

†† The piston looks fine and no scoring on the cylinder wall.There is a black spot on the wall that was a surprise.Itís looks like a burn stain as opposed to carbon buildup.There was a good size lip of carbon at the top of the cylinder and 1/8th of an inch of carbon on the piston top.The carbon buildup at the top came off with a lot of scrubbing with Oak wood chips but the black stain remained.Iíll post a before and after picture.

††

†† So the questions are:

†† Does the breather cover close air tight or just come up against the cover?

†† Is the black spot just a stain or indicate something worse?

†† The pictures show dark areas extending around the exhaust valve under the area of the gasket. Itís seems to be a leak but must have been small as I did not notice any smoke from that area. There was a bit of smoke from the muffler so maybe it masked smoke from a gasket leak.?? Does that look like a leak?

††† Just did some quick price checking on the net.††A ring set is $12 and a rod $27.† The rings should be replaced as a given but the rod and it's bottom retaining part look fine.† Would it be brain dead not to replace the rod even if it looks fine?† I was thinking of a minimum job of rings and lapping the valves so iffy about a new rod or even a piston.† What's usually done?

trouts

This message was modified May 24, 2008 by trouts2
friiy


Location: Las Vegas, The Desert
Joined: Apr 12, 2008
Points: 600

Re: Small engine repair questions, Tecumseh HSSK50
Reply #9   May 25, 2008 10:25 am
That engine looks like it burns a little oil...

The black spot is just a hot spot on the cylinder†wall next to the exhaust valve,† a little burned/ glazing oil there.. (just break it up if you hone the engine).†††††

I have seen people bust the breather by sticking their finger in the hole and bending the reed valve out of limits.

the rod I check by checking for a knock when its running under heavy load, if the engine is apart I torque the rod to the crank and check for play. I would not change the rod unless I found a problem.

The staining of the case around the valves where the head gasket sits is a leak,† sometimes the engine will make a "chirping noise" when cold, the chirp sometime goes away wen the engine heats up, but the leak is still there..

Rotory is a dealer supplier, if you can find a dealer †you may be able to save a little more.

Your 5 hp with the scored crank,† I bet 50/50 the crank is good,† the crank likely has aluminum melted on it, (kinda like crayon wax on a smooth wood table).† the way to remove it without damaginge the crank is to use pool acid (muratic acid....spelling?)..†† take† a Q-tip and dip it in the acid and wipe it around the†area of the crank surface, if it†is† aluminum, the area will turn grey and bubble, repeat until clean and smooth.†† Do not let the acid stay on the metal any longer than needed.† Overnight acid will start to cause surface rust† (even the fumes),† so apply the acid by hand,† rinse with water, then spray the crank with† oil or wd-40 to displace water and prevent rust.

If they wan't to sell you only packs of 6, let me send you one pack and you can see if you like it.. (epoxy). Email me with your info/address

Good Luck,

Friiy

trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Re: Small engine repair questions, Tecumseh HSSK50
Reply #10   Jun 4, 2008 8:52 pm

Friiy,

†† I finally got around to picking up some Muriatic acid and working off the aluminum smudges on the older 5hp crank.Itís looking pretty good and I think smooth enough to be used again.I canít feel any bumps or depressions or see any imperfections.It got a light finish sanding with 600.Thanks for suggesting the process.I thought it was unsalvageable after first looking at it.

††

†† The above motor requires a rod, rings and piston so somewhat expensive.There are two other motors here waiting for parts and tools which Iíll probably try first.A newer 5hp which needs rings and rod and a older 7hp which just needs rings.The experiment candidate is the newer 5hp so if I goof up it will be less expensive.

By the way the newer 5hp crank weighs 3.69 and the old 5hp 4.77.Quite a difference.

The rest of the parts and tools should be in by the end of the week so maybe in two weeks Iíll have a couple engines done and tested.

trouts
trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Re: Small engine repair questions, Tecumseh HSSK50
Reply #11   Jun 8, 2008 8:46 pm

Stumped again.

†† The original ring set has been replaced with a new set that adds some features.The old compression ring did not have an internal notch or bevel on either ring.The new compression ring does.That seems ok.The oil wiper ring (second ring) has a stepped notch on the outer face and that also seems ok.Both match the book I got from the library but the original old rings donít (no bevels or notches on either ring).I think the new set is Tecumsehís updated replacement set and ok.The ring set is 40006.

††† The problem part is the third ring.Itís a very different design that the old ring.The old ring was one piece with cutouts for wiped off oil to go to the crankcase.†† Thereís an expansion ring behind it.The new ring is a very different design with a top and bottom ring and also a spring ring that goes between them.

††† What Iím not sure about is if the new design eliminates the need for the expansion ring.There are two issues.

1.†††††† Should the expansion ring be used with the newer style oil return ring (third ring)?

2.††††† If it should be used, given itís age and I think spring steel then is it always replaced or just used again?

†† Itís confusing because the way my book reads the expansion ring is something that would be inserted when the motor was getting old and the oil return ring might need some help being pushed out.I did not expect to find one in a motor that had never been opened before.

trouts

friiy


Location: Las Vegas, The Desert
Joined: Apr 12, 2008
Points: 600

Re: Small engine repair questions, Tecumseh HSSK50
Reply #12   Jun 9, 2008 12:49 am
Hey Trouts,

You should not have to use any rings or ring parts†over again.†† The new rings are just better for oil control and completely diffrent..††† Did they send a picture or piece of paper showing the correct orientation of the new rings?†

Be sure to clean the ring grooves if you reuse the old piston (a piece of a old ring ,ground flat , to drag throught the groove and remove carbon).† Be sure to put the piston and rod back in its original orientation.†† If you did not mark them, check that PDF file that Dennis put† a link to.†

Good Luck,

Friiy

trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Re: Small engine repair questions, Tecumseh HSSK50
Reply #13   Jun 9, 2008 1:30 pm
† The ring set was a Tecumseh set and did not have any paperwork in the package.

†† The manual you mentioned I think was the Tecumseh 3-11hp engine manual.††It has a good explination of the bevels and notches and their orientation on the piston.† The compnents have been cleaned up so ready to install.†

trouts

trouts2




Location: Marlboro MA
Joined: Dec 8, 2007
Points: 1289

Re: Small engine repair questions, Tecumseh HSSK50
Reply #14   Jun 13, 2008 9:42 pm

Got it back together but it wonít fire up.On the first pull it gave one cough and belched some smoke and would not fire again.I took the head off and there was oil on the gasket, block and head surfaces by the gasket.

†† The gasket looked good and the head flat except for some slight curl at the very edges of the head and block.I fine filed those off and the head and block seem flat Ė at least with the straight edge I have held to the block against a light.

†††I buttoned it up, torqued the bolts to 200, and putting some talcum powder around the block and head joint.†† On pulling the start rope it blew away the talc at the gasket at the middle side head bolt.The head must be warped.It leaks from the side.

†† The engine had a broken rod so ran before the parts were installed.All I can think of is the rod must have pushed the piston into the head.Thereís no sign of any contact though so puzzling how the head or gasket could leak.??

  1. Is it common that a head would be warpped after a rod breaks?
  2. Getting it machines would be to expensive.Is it possible to get it within service tolerance (what ever that is) by hand?Can it be flat filed or ground on a flat plate.A friend made a plate for me 17 x 17 inches flat across the diagonal to a 10 thousandth.The gasket seems to hold at the valve and cowling ends but bowed up in between.
  3. How can I deal with this?
trouts
niper99


Location: London Ont
Joined: Dec 2, 2007
Points: 337

Re: Small engine repair questions, Tecumseh HSSK50
Reply #15   Jun 13, 2008 11:31 pm
trouts2 wrote:

Got it back together but it wonít fire up.On the first pull it gave one cough and belched some smoke and would not fire again.I took the head off and there was oil on the gasket, block and head surfaces by the gasket.

†† The gasket looked good and the head flat except for some slight curl at the very edges of the head and block.I fine filed those off and the head and block seem flat Ė at least with the straight edge I have held to the block against a light.

†††I buttoned it up, torqued the bolts to 200, and putting some talcum powder around the block and head joint.†† On pulling the start rope it blew away the talc at the gasket at the middle side head bolt.The head must be warped.It leaks from the side.

†† The engine had a broken rod so ran before the parts were installed.All I can think of is the rod must have pushed the piston into the head.Thereís no sign of any contact though so puzzling how the head or gasket could leak.??

  1. Is it common that a head would be warpped after a rod breaks?
  2. Getting it machines would be to expensive.Is it possible to get it within service tolerance (what ever that is) by hand?Can it be flat filed or ground on a flat plate.A friend made a plate for me 17 x 17 inches flat across the diagonal to a 10 thousandth.The gasket seems to hold at the valve and cowling ends but bowed up in between.
  3. How can I deal with this?
trouts


trouts

did u check compression?, is the head gasket new or old ? l personally have never seen a head warp badly enough that a new head gasket wont fix.

Replies: 6 - 15 of 25Next page of topicsPreviousNextNext page of topicsAllView as Outline
Outdoor Power Equipment (Lawn Mowers, Snow Blowers, Chain Saws and more) Guide   •   Discussions  Reviews  
AbbysGuide.com   About Us   Terms of Use   Privacy Policy   Contact Us
Copyright 1998-2014 AbbysGuide.com. All rights reserved.
Site by Take 42