1996 Suzuki DT65. SEIZED!

[Huebillionaire]

Motor is seized. That's for sure. Overheat.

Been soaking the cylinders for 36 hours with ATP, pb blaster, and seafoam. Is probably friction welded.

Hooked up an air line to a spark plug adapter, putting 100psi into each cylinder to force any penetrating fluid into the rings.

Only the middle of the 3 cylinders even giving any sort of back pressure to read on the tire inflation gauge.

Being patient I put a torque wrench on the flywheel to 50ft pounds. I would like to avoid destroying bearings etc. Should I just stop and pull head off and dig deeper before I shear the flywheel key or do any more damage to the cylindar walls. The lower end is in great shape, aswell as everything else.

 

[99yam40]

with an overheat, I would pull it apart to inspect the cylinder walls and pistons.

but a locked up lower unit could also stop a motor from turning,
drop the lower unit to rule that out

 

[Huebillionaire]

with an overheat, I would pull it apart to inspect the cylinder walls and pistons.

but a locked up lower unit could also stop a motor from turning,
drop the lower unit to rule that out

The lower end shifts smoothly. Its in neutral.

Next step pull cylinder head?

 

[Sea Rider]

Have had severe overheats due to lower water intake blockage at full throttle, but once the motor cooled down was able to turn the motor, not start it back again due to having a shot head gasket. At which rpm, throttle range happened the overheat ?

That's a 2 or 4 stroke motor ? Was the fuel oil ratio mixed in the right proportion, was the crankcase filled with enough oil level ? If the flywheel won't turn with a wrench, better tear the whole powerhead to avoid extra internal damage.

Happy Boating​

 

[Scott Danforth]

There is no magic mechanic in a can to bore and hone your block, and swap pistons and rings after an overheat that siezed a motor. Start by pulling the power head

 

[Huebillionaire]

Have had severe overheats due to lower water intake blockage at full throttle, but once the motor cooled down was able to turn the motor, not start it back again due to having a shot head gasket. At which rpm, throttle range happened the overheat ?

That's a 2 or 4 stroke motor ? Was the fuel oil ratio mixed in the right proportion, was the crankcase filled with enough oil level ? If the flywheel won't turn with a wrench, better tear the whole powerhead to avoid extra internal damage.

Happy Boating​

 

[Huebillionaire]

Have had severe overheats due to lower water intake blockage at full throttle, but once the motor cooled down was able to turn the motor, not start it back again due to having a shot head gasket. At which rpm, throttle range happened the overheat ?

That's a 2 or 4 stroke motor ? Was the fuel oil ratio mixed in the right proportion, was the crankcase filled with enough oil level ? If the flywheel won't turn with a wrench, better tear the whole powerhead to avoid extra internal damage.

Happy Boating​

All I know is it was getting some oil but the ram wasn't connected to allow more oil injection at higher rpms. So it was not getting enough oil but some. It's a 2 stroke.

 

[Huebillionaire]

I went out this afternoon.

Pulled the cylinder head cover, gaskets and cylinder head.

All the cylinder walls were rusted. This boat was run less then a month ago. On the cylinder head the ring was broken as well as the gaskets were in terrible shape. It appears water ingressed into the top cylinder, and subsequently into the others. Is this hydrolocked? See pictures and video link.

Any insight would be great thanks.

 

[Sea Rider]

For me it's rust locked, yep too much water intrusion due to faulty dried, hardened, shot head gasket. That's why always recommend to re torque all powerhead gaskets at first 5 run hours from out of the box or when installing new ones in, all gaskets will have ceded a bit due to heat, a high quality torque wrench will indicate so.

Need to tear the whole powerhead down, soak the cylinders and stuck pistons with penetrating oil, WD-40 overnight, be gentle when removing the pistons out the cylinders. Is it possible to remove the crankshaft while the connecting rods stays in place, if so much better. Will need to bang out each piston gently with a wooden bar, inverted wooden, hard plastic hammer till each piston is removed.

Check overall cylinders condition, if not scratched, clean them with sanding paper with thin grade, install new piston rings, clean well both cylinder head's mating surfaces, install a new head gasket. Take advantage to manually decarbon the entire exhaust covers, and internal cylinder head. A fun work that will take some time....

Happy Boating​

 

[Huebillionaire]

The mixture

For me it's rust locked, yep too much water intrusion due to faulty dried, hardened, shot head gasket. That's why always recommend to re torque all powerhead gaskets at first 5 run hours from out of the box or when installing new ones in, all gaskets will have ceded a bit due to heat, a high quality torque wrench will indicate so.

Need to tear the whole powerhead down, soak the cylinders and stuck pistons with penetrating oil, WD-40 overnight, be gentle when removing the pistons out the cylinders. Is it possible to remove the crankshaft while the connecting rods stays in place, if so much better. Will need to bang out each piston gently with a wooden bar, inverted wooden, hard plastic hammer till each piston is removed.

Check overall cylinders condition, if not scratched, clean them with sanding paper with thin grade, install new piston rings, clean well both cylinder head's mating surfaces, install a new head gasket. Take advantage to manually decarbon the entire exhaust covers, and internal cylinder head. A fun work that will take some time....

Happy Boating​

Well I did most of that this afternoon!
I took off air box, carbs, reed valves. To see the crankshaft. Verified what I thought. Rusted.

I was unable to move the number one cylinder rod bearing. Yet #2 and #3 I could move vertically. Tapped all cylinders with a wood block. Nothing.

Sprayed MMO, pb blaster and 2 stoke oil directed into troubled areas.

Try again tomorrow!

Thanks for the help so far

 

[99yam40]

rusted crank and bearings?
what do you plan on doing to clean that all up?
or junk the motor?

 

[Huebillionaire]

rusted crank and bearings?
what do you plan on doing to clean that all up?
or junk the motor?

Buy a new crank shaft. They are only 150 bucks on ebay. It's a very clean motor I got for next to nothing. Be a sin to toss it!

What do you think. Just can't find a cylinder head online. Has anyone ever repaired a cylinder head ring?

 

[Sea Rider]

Yes, a machine shop can clean any rusted cylinder once the crankshaft is out. A pity that such crankshaft is a one piece factory assembled, will nee to tear it to remove the upper cylinder's crank pin, connecting rod and bearing, order a new crank pin and bearing. If the connecting rods are good to go can keep them along all what's housed at the other end or even install 3 new piston's rings which are friendly to change.

Happy Boating​

 

[Faztbullet]

You cannot repair crankshaft unless you have the jig fixture to hold journals in position while pressing back together.

 

[99yam40]

some have no idea the crank and rods come as a set.
and there are very specialized tools needed to take apart and put back together.
getting the pistons out of a motor that will not turn/rotate is not an easy task

 

[Huebillionaire]

I pulled powerhead.

Got the crankshaft out and the #1 bearings, connecting rods and piston bearings were all seized.

The other two cylinders moved freely. Pulled the pistons off and bearings off and labelled and bagged them. They came off easily and are in good shape. No scaring on the pistons.

I'm going to work to put in a everything in a agitating varsol bath for the day.

Depending on the outcome of that I will start the ordering process of about a dozen things i need to replace.

Once fully assembled. Any special tools required to facilitate the install of the pistons back into the cylinder?

For your situational awareness, I am on Parental Leave from work for 4 weeks. Got about 4hrs free a day to work on it.

Thanks everyone,

 

[Huebillionaire]

One of these things is not like the other.

 

[Sea Rider]

So managed to remove the crankshaft out, great progress. What was the condition of the first cylinder sleeve, aside from being rusted, has shallow or deep scratch signs ? Nope can't tear the crankshaft at home, a machine shop will measure it properly, remove the upper crank pin to remove the lower connecting rod's shot bearing, install a new one in, assemble it back.

Let's hope the current crank pin is not shot, new ones seems are NLA, in that case that machine shop will need to make a new SS one. What do you plan doing with the overheated discolored piston ? Plan replacing all 3 pistons along their piston's rings ?

Lower cylinder sleeves should have a 2 diagonal cut one in front of the other that facilitates the piston's rings compression while the piston makes its way inside the sleeve., if not will need to get a ring compressor tool.

Happy Boating
​

 

[Faztbullet]

That crank on number 1 is toast. No amount of soaking will bring it back to life. You CANNOT have machine shop make a S/S one as it has to be steel and bearing surface hardened to a 6-8 mil depth. Even if machine shop could make one they dont have the jig to reassemble crank throws. Sea has apparently never had one of these apart. Best to get a reman crank or used.

 

[Sea Rider]

Sea has apparently never had one of these apart. Best to get a reman crank or used.

Don't jump to conclusions with me, let me enlighten you. Tohatsu motors have a one piece assembled at the factory crankshaft. When there's no crankpin to replace specially when moron boaters capzizes in salt water and the motor is not immediately taken care of, the crankpins gets rusted, shot and if new ones are not available my highly skilled Machine Shop fabricates them with SS steel which are soon after hardened at a hardener facility.

Then is pressed back with a new needle bearing and new connecting rod if needed to the exact measurements it was assembled prior tearing the crankshaft down. This is not Space Rocket Science and seems incredible to me that you speak in behalf of all the machine shops in the entire USA.

If you pride yourself on being the know all cool guy should have posted that precise info to the OP, not to me way before my last post. With all the tech information given, it's up to the OP what he wants to go for...

Happy Boating​