OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Suzuki 2 stroke rebuilds.

Hi, I have striped down 2 x Suzuki engines and thought I would share a few images.

This engine was dirty inside, but no where near as dirty as the second one.


Might be hard to see but this image shows the cast iron sleeve held in by a spring clip. Because there is no head to remove on these, the carbon is hard to remove, I use a bearing scraper and then a wire wheel on a drill extension.


Crank case halves.


Before I pulled it down, this engine felt better to turn over than the first one.
The bottom seal was completely full of muck. I will put up some images of the bore when I clean it.




To rebuild these, your pretty much just need rings, bearings and seals.

I want to put a remote filter up on the handle, but not sure how to go about it yet.
I also have to source some bearings.

Those are just an ordinary 6004 and 6005 ball-races Mark, you can get them on any street corner:
http://www.ebay.com.au/itm/Deep-gro...d_Tools&var=&hash=item258e82275e

I had to put new main bearings in an Echo trimmer recently and used sealed ones instead of open ones because they were cheaper. However to do that you have to check two features. First, measure the actual width of the old and new bearings, making sure they are the same. My sealed ones had a slightly wider inner ring, so I ground it down to the original width. The other issue is whether or not you have to remove the rubber seals with a knife point or scriber. Some engines rely on having fuel/oil mixture pass through the bearings to lubricate some other feature of the engine, but most do not. After having a close look, I left the seals in place, and the Echo engine seems to be happy that way.

Here is the dirty engine cleaned up.




This bore only needed a light honing. New rings pretty much just slide in if oiled as the bore has a good taper on it.


Governor arrangement with arm fully rearward.

Excellent pictures, Mark - up to your usual standard, in fact.

Hi Mark,
Very interesting rebuild(s).
Would be strange not being able to 'take the head off'.... Recently acquired a Dremel as a birthday gift, looking forward to using it but I guess it wouldn't be suitable in this case?
Did you replace the big end bearings in these?
Will bookmark this as want to overhaul my one one day. Any details will be appreciated.

Thanks for the info on the bearings Grumpy, I ended up ordering a bulk lot that covers Suzuki and Victa full cranks. (One of the sizes suits both).

Bushie if you have any questions I will answer them if I can. Really they are not hard to get apart and put back together. For me with a new type of engine it is daunting the first couple of times and then I find I just rip them apart without thinking to much.

The most difficult part is setting up the governor and carb, then tuning it. But if everything is clean and right it should fire first pull.

With regard to the big end bearing, I moved it around and inspected it best I can, give it a good spray and clean out and oil it up. Haven't had to change one yet.

I want to put a snorkel type air filter on one of these. Here is the filter box.

Notice the fan throws air into the box so that it can then be drawn across the all of the foam filter.

I would have to block that inlet off and attach the snorkel to the box somehow. Not sure how it would affect performance.

I would like to attach straight onto the carb if I could and remove the box altogether.

Any ideas?

I really dislike any filter down at the engine where all the dust is. I will put a snorkel one on when ever I can.

I have several of these, one a horrible looking despicable mess, no paint on the cowling, just before I went to put that one back where it came from I thought I would have a fiddle with it, the carb had been run dry, the starter knob is a peice of fencing wire and the whole kit looks like it had been outside for at minimum 10 years.... bugger me dead it went second pull and after the initial run goes first pull, its a horrible looking machine since I am still yet to paint any of it but performs flawlessly, probably even better if I went to the 50:1 on the fuel cap over 25:1....

They are a very nice very smooth 2 stroke engine with tons of power to boot.

Great pics Mark, I find it very interesting different engine designs this seems to be a clamshell design.. What do you use to seal the clamshell cases? I find ThreeBond works great and around the seals as well you don't want an air leak past the outer part of the seal.. Some use say a loctite bearing retaining compound to stop the bearings spinning in the case halves as clamshell clamping force is not that great some say, I have never used it yet but I have seen a few spun bearings in clamshell engines...Cheers Chris

Mark Electric, just for your amusement, I want to show what your
air filter looks like in a unit that is not serviced. enjoy.

Love the air filter design Christo, it definitely made me laugh.

G'day MrMckay, They are known for their longevity. I haven't come across scored bores in these, no matter how dirty they are inside. The only one I scrapped had a broken ring, because it wasn't assembled right.
There are a lot of these in the USA used on commercial machines, hover mowers & snowblowers. Here is a thread in America discussing Suzuki or Toro 2 cycle engines.

http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/1868612/1

Chris, thanks for the tips, I use this to seal the crankcase.


In the 2 manuals I have, one states:
5. Assure both halves of the crankcase are clean and free of grease and old sealant.
Apply a thin uniform amount of Threebond #1104 or Loctite #515 sealant to the mating surfaces and position the crankcase halves together.

The other manual: recommends Suzuki bond no.4.

Christo, love the filter. That one will need to pulled down and cleaned out.

The reason these engines fail is:
1. Air filter as above
2. Choked fins stopping cooling
3. No oil in the fuel

A lot get discarded because they have diry carbs and water in the tank.
I live in a rural area, and ones I get are not good, I'm sure somewhere on the mower is says please trash me.


Below is what I came up with for the snorkel.

While I thoroughly agree a remote air cleaner by way of a snorkel is by far a better design for clean air, but the very innovative way Suzuki put the fan air blowing into the filter is almost a mild turbo, so you may get performance issues.

If one could put a snorkel to the fan would solve this but I imagine tube and filter would have to be a big diameter to not impede the engine cooling capacity.

Yes Bushie I agree, I will try it to see how it goes, it is only 2 x 10mm nuts to put it back to original.

I have striped 3 of these engines now and have put what I consider the worst one back together.
With the carb and governor set up, I remove everything now (carb, governor arm & throttle control plate) assemble all the linkages then put it all on the engine in one hit.
A tip is to scribe a matching line on the governor arm & shaft before removing it.
This arm is reassembled with the shaft rotated fully clock wise the arm fully rearward.

I have drilled the jet out the next size up 0.85mm. Will let you know how it goes.
I had to straighten out the linkages and springs as they where a mess, if they hadn't been played with, it would tune up a lot easier.

I have put a mower together and tested it, this is he dirty engine that I honed out with used rings, bearings and seals. (I got impatient waiting for parts). With a jet size of 0.85mm

I don't recommend drilling the jet out larger, I wished now I had tried it first, then drilled the next size up to notice a difference (next time).

It is starting around 4 pulls and I had to lower the revs by 150rpm by moving the governor spring down a hole.

There was no noticeable difference in how the engine ran using the snorkel air filter or the original. So I stuck with the snorkel.


More worrying is the vibration in the handles, I fitted new blades with no change, anyone have a fix for the blade plate, I don't have a balancing cone.

Hi Mark, re-fitting used rings to a new or different cylinder surface is not recommended practice. I've only tried it once myself, on a Honda GXV120, and it failed miserably. I'd fitted new rings to a worn bore, and they'd bedded in nicely, but after 8 hours running I scrapped the block and put the parts (including the piston and rings) into a better one. The engine immediately had substantial blow-by, and it didn't get better. After a couple of hours' running, I fitted new rings and immediately, all was well. I've often put used rings back into their original bore of course, and had no problems, but I can't say I recommend putting them into a different bore, or a newly-honed bore.

Thanks for your experiment, I didn't feel right while I was putting it together, but I kept going, why do I do that.

I want a nicer engine on the red Big bob base anyway, so I have pulled down a 4th one that was as clean as a whistle inside, I will use this one.

Unless there is a chunk or so missing from the blade disc, it won't be a balance issue anyway. It could just possibly be bent, though.

It's a little difficult to check, but can be done on the mower. The way I'd do it, is to tip the mower over, and take the blades off. Then set up a magnetic base under the deck, to hold a rod just in contact with the bottom face of the disc, and turn the disc by hand, to see if any 'wobble' is evident. The fluting and bolt recesses of the disc make using a dial indicator impracticable, and that level of accuracy isn't necessary anyway.

A bent crankshaft will also produce wobble here, but that's very unlikely for an engine that has had a flat blade disc fitted. Bar blades are a very different story...

If the disc is bent, replacement is the simplest fix - the ODK Shop has it HERE.

Just a tip if you're planning to keep the Big Bob; they cut much more neatly if fitted with four blades. Handle heavy going better, too.

Thanks Gadge, I fitted the new engine today and it is running great. The old one I will put aside for parts.
This time I did put 4 blades on, but the vibration is still there. It is the plate that is at fault.
I have never thought to check for wobble in the plate. So I will do that after lunch.
Cheers hey
From Mark

There was a 4mm difference from one quadrant of the plate to the next.

I got another plate of an old Little bob, which stopped the vibration, there is still a little bit there but it is much better.

Again I will have to slow this engine down.

It is starting on the second pull.

You can tell a good engine when you pull the starter by the noise it makes and the feel of the compression, this has come with experience for me.



I have other engines here waiting for parts that I will put together off this thread.

Gday Mark, I have been following your thread closely as I have returned a fair few suzuki back to service over the past 12 months. I have not however stripped one back completely like yourself so your thread has been excellent to read.

I dont mean to hyjack your post but wanted to ask a question. I was recently putting together a suzuki, piston, rings main engine were all good until I got to getting the emulsifer out of the carby. My normal practice is to soak the emulsifer in carby cleaner for a few hours before attempting to remove it. To date I have never had a problem. Until recently,when I noticed the current one I have is very damaged and its unable to be removed. I dont want to put the carby back together without cleaning the emulsifer properly as I have found from experience this is imperative to gettign the engine running correctly.

I dont suppose you have any suggestions when it comes to removing damaged emulsifer head.... I am thinking the carb might be trashed and I'll need to wait until I find another suzuki engine as a spare!

Again great thread, Im a keen follower.Keep the photo's coming.