compression problem

[tiplickhahaha]

info:
1988 piston port 550
all stock (engine)


just put together the engine and started it

and this happens:banghead: :banghead: :banghead: :banghead: :banghead:


i take it where the waterjacket hose on the cylinder head is piston #1?


ok 120 psi compression in this one and only 20 psi compression in cylinder number 2

from what i read, it could be a ring problem? i dont think so as i justinstalled the rings per manual. everything was perfect. i even compression tested it and both turned out 120. then a couple starts next this happens.:banghead:

i never really put it in the water, although i did run it on the hose for a couple of minutes....

the two things that could have screwed me is perhaps the crankshaft? a bent rod a blown bearing? i know the crank was old and didnt pressure test it....(i wish i had:banghead: :banghead: )

or maybe not adjusting the carb..another fault of mine? it's the SBN 44 and i didnt touch it from stock..but it did run on it so i doubt it's a lean problem as i still have compression is cylinder #1

anyhelp guys?

thanks :cool2:

PS>> i'll pull the head off tomorrow and snap some pictures,,

[550 SLUT]

the #1 cylinder is the front one by the front of the ski

as for compression was fine before u stated with gas?

sounds like the ring did not seat properly
120 psi is low but u should be ok

snap pics lets see

[Aka Kane]

Definately low,

but he won't be ok because he has 20 in cylinder number two...I don't know what to tell you man, but that is a pretty isolated problem.

[tiplickhahaha]

that’s what I was afraid of...


I gaped the rings properly and didn’t hold the throttle down much. I would say maybe under 10 minutes of total run time before the compression went to 20. I will post some pictures later today with the head off.

[john zigler]

it could be almost anything. you will need to pull your cyl. as well.

did you bore the cyt? did you add a nice champher to your ports? you could have snagged a ring on a sharp port edge.

you may have had a c-clip come out.

it might have just overheated, and stuck a ring.

what was you piston to cyl clearance set at?

get us some pics.

zig

[tiplickhahaha]

I have this on pwct but i figured i should update this thread

http://img1.putfile.com/thumb/10/28119063917.jpg (http://www.putfile.com/pic.php?img=3633864)

http://img1.putfile.com/thumb/10/28119063925.jpg (http://www.putfile.com/pic.php?img=3633863)


it might be improper clearance i dont know hopefully this will shed some light on the problem

[550 SLUT]

what are the clearances?

looks like the ring snagged the exhaust port
u gapped them right?
and the ring clearance was correct?

[tiplickhahaha]

thanks for the reply on pwct. rings are fine, i took the cylinder off and have the pistons still connected to the rods in the hull. std clearance. i read up on four corner siezure and group k said overheating? on a new engine? there are "streaks" on the piston that siezed. :bigeyes:

[MrSki]

I'll go look for the PWCT thread but it got too hot and seized. Need to figure out why. Was the hose on, was it running through the cylinder of just the exhaust, air leak into the carb fuel line....?

[tiplickhahaha]

Here are some m ore pictures. i guess then i will need new pistons and cylinder. everytime i ran it it, watter was running through the engine. you said fuel routing could cause that? proably wrong lines.

http://img1.putfile.com/thumb/10/28219130815.jpg (http://www.putfile.com/pic.php?img=3643749)
http://img1.putfile.com/thumb/10/28219130820.jpg (http://www.putfile.com/pic.php?img=3643748)
http://img1.putfile.com/thumb/10/28219130876.jpg (http://www.putfile.com/pic.php?img=3643747)
http://img1.putfile.com/thumb/10/28219130713.jpg (http://www.putfile.com/pic.php?img=3643746)