My Small Engine Projects

Crazy_Carl wrote:

You should pull the crank, weld it up and take it to your uncles lathe to drill and tap it the right way

Good idea, that may be the best solution.

CraftsmanQuad19 wrote:

I’d say screw it and weld the blade and adapter to the crankshaft lol

I'm sure there's a better solution haha. I'd like to be able to remove the engine if I need to CQ.

Well, I think I need to get a new crankshaft for this engine. If I were to weld the hole up, it would be way too hard to thread it. So I'm going to put a wanted ad for any old Briggs and Stratton 3.5's on gumtree. I need the older style one with the starter clutch extension on the top. I could take the crank out of the 3.5 that I was going to build up but it doesn't have the starter clutch bit on the top of the shaft. I was wondering if I could cut the starter clutch piece off the banjaxed crank and weld it onto a crank that doesn't have one?

Was at a Steam Rally today, came home with some goodies.

Got a 75cc Suffolk engine that has been brush painted blue, a shroud & recoil and a fuel tank for £9. 


I originally just wanted the engine for the Zenith 13-TCA carb for my other Suffolk but after taking the head off I realised there is less wear on this engine than my other one so I'm now going to get this one running. Been looking for a recoil for these engines for a while, it isn't the 'rarer' older style one but it is better than using a rope wrapped around the starter cup. Btw it also has a homemade exhaust.
 

There was no head gasket on it but I think I have one laying around but if I don't they are only £3 on ebay.

It had no spark so I took the flywheel off but stupidly forgot that the nut on the flywheel is lefthand thread and ended up destroying the threads on the crank. The nut would have needed replaced anyway. So I think I may have to replace the crank with one from my other engines, or die it to a slightly smaller size thread. The size of the nut is 9/16.

What a bummer about those threads man.  

Pretty neat looking motor.  I like where the dipstick is.  Is that an exhaust made from copper pipe?

Yeah the briggs model 5s's are reverse threads on the crank too, annoying... Oh well, it happens. Neat find!

Crazy_Carl wrote:

What a bummer about those threads man.  

Pretty neat looking motor.  I like where the dipstick is.  Is that an exhaust made from copper pipe?

Well I think I got it sorted. Yeah the dipstick is nice, you can check the oil level by taking out the stick without unscrewing the threaded cap. Yeah the exhaust is made out of copper plumbing bits and pieces.

mr.modified wrote:

Yeah the briggs model 5s's are reverse threads on the crank too, annoying... Oh well, it happens. Neat find!

Yeah the Briggs Model 5s and Suffolks are near enough the same. 

Anyway, I died the threads out to M10, seem ok. I tightened the flywheel up quite tight and they seemed fine. Before I put the flywheel back on I cleaned the points to try to get spark.

Cleaned up the piston, valves and head and fitted a nearly new head gasket.

I also bolted the starter to another shroud I have with bolts to hold the tank on and put the green tank from my other Suffolk on.

I put her all together but there's still no spark. I think the problem is I set the gap on the points too small so I will set it properly tomorrow.

I also took the Briggs of the lawnmower. I'll strip the engine down and take out the crank and see if I can get a replacement. She still runs pretty good even without the blade (I think it has a slightly heavier aluminum flywheel) so it would be a pity to not have her mowing again.

That's a very interesting shape to that deck stamping. Looks like it's supposed to funnel into a bag attachment. My parents have a honda with a similar shape but not as extreme as this one. Does it make it harder to work on the motor?

MatthewD wrote:

Anyway, I died the threads out to M10, seem ok.

Matt! You died? I sure hope not.

*LAME JOKE ALERT*

Crazy_Carl wrote:

That's a very interesting shape to that deck stamping.  Looks like it's supposed to funnel into a bag attachment.  My parents have a honda with a similar shape but not as extreme as this one.  Does it make it harder to work on the motor?

Yeah, I'm not too sure why the shape is like that. It looks pretty cool though. Working on the engine isn't too bad, as the back of the engine is the only bit that you can't really access.

Double W Cross Ranch wrote:

MatthewD wrote:

Anyway, I died the threads out to M10, seem ok.

Matt! You died? I sure hope not.

*LAME JOKE ALERT*

We've been through this already on the chat W

MatthewD wrote:

Double W Cross Ranch wrote:

MatthewD wrote:

Anyway, I died the threads out to M10, seem ok.

Matt! You died? I sure hope not.

*LAME JOKE ALERT*

We've been through this already on the chat W

I know but I still wanted to post my lame joke because I can.

I was there, it was a pretty lame joke. I was the one who turned on the *Lame Joke Alert* Hahaha. Nice job Matt! Hopefully those new threads on the flywheel will hold up for ya.

Thanks Allis, the threads are better than the look tbh.

Finally got the points adjusted to 20 thou. It took me a while to work out how to adjust the points properly. The adjuster is circled in red.


Once the points were adjusted there was great spark so I put the shroud on and filled her with used oil (will replace it with new oil soon). Put some fuel in it and after warming up a spark plug in a Briggs she fired up! She runs great on idle but when you rev her she runs really rich. Adjusting the jet doesn't seem to help very much. Anyway, pretty pleased with her running.

Sweet. How many HP is that one?

muckmudd wrote:

Sweet. How many HP is that one?

He said it was 75cc.

muckmudd wrote:

Sweet. How many HP is that one?

Thanks. I think it's around 1hp.

Double W Cross Ranch wrote:

muckmudd wrote:

Sweet. How many HP is that one?

He said it was 75cc.

CC (cubic centimetres) is the displacement of the engine (75cc=4.5ci)

I think I've got the rich running problem sorted out, the jet/threads were corroded and needed a bit of persuasion to move in.

So I'm thinking of displaying a couple of engines at a few steam rallies and shows and I want to have this engine running something. I'd rather not have a water pump because that's quite common. I was thinking of having it run an air compressor which in turn runs the compressed air Suffolk I have.

MatthewD wrote:

I was thinking of having it run an air compressor which in turn runs the compressed air Suffolk I have.

That would be cool for sure!!

MatthewD wrote:

Double W Cross Ranch wrote:

muckmudd wrote:

Sweet. How many HP is that one?

He said it was 75cc.

CC (cubic centimetres) is the displacement of the engine (75cc=4.5ci)

I know, but typically it can be used to rate how many hp it has. For example, 212cc is about 6.5 hp.

Double W Cross Ranch wrote:

MatthewD wrote:

Double W Cross Ranch wrote:

He said it was 75cc.

CC (cubic centimetres) is the displacement of the engine (75cc=4.5ci)

I know, but typically it can be used to rate how many hp it has. For example, 212cc is about 6.5 hp.

Not really, if it's OHV it will be a smaller capacity than a flathead.

Made a throttle linkage for the governor as this one didn't have one and hooked up a spring. The spring is a little on the tight side but it should be okay. I'll get a picture of it later. 

Anyone any other ideas of what to run with this engine?

Double W Cross Ranch wrote:

I know, but typically it can be used to rate how many hp it has. For example, 212cc is about 6.5 hp.

No that's definitely not true. Could depend on induction, carb, head, valves, max RPM, etc.

Nah, that doesn't really prove anything at all. There is obviously a relationship between the two, but displacement is not the only thing that defines horse power. But anyway, let's refrain from jacking Matt's thread any further.

Yeah generally you would except the displacement to increase as the hp increased, but there's no formula or definite answer because there are too many variables as Allis previously mentioned.

OKAY LETS STAY ON TOPIC FROM NOW ON

OK Matt I have something on topic! I think you should run an air compressor or a generator with it. maybe you could make a 12 V generator by using a car alternator for charging batteries and as an alternative 12 V power source.

Yeah I think running a generator would be pretty nice. I could use a large car alternator with a belt to the pulley on the Suffolk. Would an alternator from a car be able to run lights and stuff? That might be cool to have as an engine display.

Here's a photo I took quite a while ago (can't remember where, some small engine show/steam rally probably) of a Suffolk driving a small alternator which is what I want to do.

Ooh, giving me ideas.

To get the alternator to turn on, you need an external power source, like a battery to charge the field so it can magnetize. But once you get the alternator to turn on then you don't need the battery any more. A generator is different because a generator has permanent magnets in it and doesn't need an external power source to turn on, just need to spin it.