[dustman2014]

Hello all, this is my first post. I just did a complete engine teardown and rebuild on my 11 HP Tecumseh Formula OHV engine. Engine model OH318EA, Spec 222712E. Engine will only turn over by hand when I turn the flywheel, and it is VERY stiff... I have rerplaced all rings, seals, gaskets on the engine from the crank up, and have set the timing marks on the crank and camshaft gears to match one another. When I finish reassembly, putting recoil housing on, it is not strong enough to turn the engine over. Why is the engine so hard to crank/turn over?

 

[Basementgeek]

Hi and welcome to TSF

Got oil in it? Cylinder walls have oil on them?

How is it to crank with the spark plug out?

Did you adjust the valves ?

BG

 

[dustman2014]

Hello and thank you for responding to my question. Yes there is oil in the cylinder walls and before I put the head on I even sprayed some extra lubricant on top of the piston and rotated the engine manually by turning the flywheel in hopes that it would loosen up. I have not even put the spark plug in yet and I have this stiff problem. I will doublecheck the valve set but would valves cause this much stiffness? Any other ideas as to what it could be?

 

[dustman2014]

Update: I tore the engine apart again in an attempt to figure out the problem. I removed the valves, and pulled off the head, and poured some oil directly onto the top of the piston, and rubbed it around on the inside of the cylinder walls. This made absolutely NO difference. With the head off and with the cylinder walls coated in oil, the engine is still extremely hard to turn over by hand using the flywheel, and the reoil will not even budge it. Any ideas as to what it could be now??????????????

 

[Basementgeek]

What caused you to rebuild it ?

Are you sure you got the correct rings in it? What all did you replace?

You may have to tear it down again to find what is binding.

BG

 

[dustman2014]

The engine was eating oil at a rapid pace and eventually went puff and a big white cloud of smoke came out and it shut down. Would not start again. I am a small engine mechanic by trade so I am very in tune with this kind of stuff. The company did send me the wrong piston rings so I researched the hell out of it and found the right ones and installed the proper rings. I tore the engine completely down to the crank and replaced both oil seals on the crankshaft along with the piston rings and every gasket on the engine. I figured while I had the engine apart I might as well replace everything. I am not against tearing the bottom half apart again but any thoughts as to what could be binding? The crank and engine free wheeled until I put the piston and the rings back in the cylinder. And that's when it became extremely stiff.

 

[Basementgeek]

Since a small engine mechanic, you know more about than I do. Wrong rings. Did you fit the rings in cylinder first and check end gap ?

BG

 

[dustman2014]

The rings are the correct rings and yes I did verify the end gap

 

[SABL]

Recheck the connecting rod cap to make sure it hasn't been turned 180 when assembling.

 

[dustman2014]

Can you please explin what you mean by the connecting rod cap? And how it would turn?

 

[SABL]

The cap can only go on one way......if rotated it will seize the crank. The holes will line up but the bore will not. The caps are installed during the milling process and the final bore is made as the last step in the machining process.

The 'flats' of the caps and rods (where the cap mates to the rod) are milled in seperate steps. They are bolted together as a single unit before the crank bore is made to ensure precision and correct alignment. The bolts will always line up but the cap can only be installed one way.

 

[dustman2014]

I will check to see but I am pretty sure its on the right way, any other ideas.......

 

[SABL]

You said the crank rotated freely until the piston was installed. The only thing I could think of after you verified the ring end gap was correct is the cap. Very easy mistake to make and will seize the crank as soon as the cap bolts are torqued.

 

[Basementgeek]

If you used the old piston, get a new one. I am thinking the ring lands are worn.

BG

 

[dustman2014]

Hey SABL, you were exactly right. I took the engine apart again last night, and found that I had put that silly/stupid connecting rod cap on backwards. I turned it around, and evenything worked. I was constantly checking as I reassembled the motor, and once all together, the engine turned great. Thank you so much for your insightful advice. For something so smalll, caused such an issue. I will deffinately look closer the next time I do this job. I guess I have got lucky in the past cause I have done A LOT of these and never had this issue. I do have a question though. I did all the typical tests once the engine was back together, ie, sprak, compression, set valves to .004, and the compression was reading 100-110 psi. I ran the engine, and it ran great for a minute or two, and then simply shut down. And I check today, and the compression is 0, but the engine turns freely, and it did not blow or puff. Is this valve relatted????

 

[Basementgeek]

Not likely, but easy enough to check. I assume your used a torque wrench when you tighten the bolts.

BG

 

[dustman2014]

Yes, everything was torqued to their propper Tecumseh specifications. What else could cause complete loss of compression?

 

[Basementgeek]

Have you pulled the valve cover and look ?

BG

 

[dustman2014]

I just did and found that one of the rocker arms had come off the valve push rod, so I fixed that, reset the gap clearance, and compression has come back to just under 100psi. I'm hopeful it will increase once the engine is running/warm??????

 

[Basementgeek]

Does Tecumseh publish compression readings?

BG