compression question

[murjiim]

this is not a seadoo but a kawi..but the idea will be same as its about compression.

this engine has 3 plugs.
the engine would not spin so i thought the impeller was siezed..that came out true actually due to sand which was found all over the jetpump.
now i thought to try to turn the engine over and the darn thing will only spin freely when all plugs are off. if i even put one plug on, press start and the it turns alittle bit then stops turning, then it turns a bit then stops. so essentially it really struggles to spin.
if i have all plugs off..it will turn over fine and when i stop pressing the start button, i can here a hiss sound like the compression or the pison is releasing pressure or something like that.
also i notice some whitish or milky residue around the plug holes.

i am thinking no compression, i am also thinking water flooded.
but if it was water flooded, i should see water splashing out of the plug holes when i press start right?

thanks

 

[Dr Honda]

Yep... with the plugs out... when you crank it... water/fuel/oil would be coming out the plug holes. BUT... if there is a question about water intrusion... I would spray fogging oil into the engine to help protect it.

It sounds like the starter is tired, or the battery is dead.

 

[murjiim]

I just put in a new starter.
What are the signs of low compression? ould it turn over slowly and progressively get slow to spin?

 

[roy4481]

get a compression tester.

 

[murjiim]

Got one..I had all plugs out and it would not even spin. Same thing as if even one plug is there its hard to spin. I just put a good charged batt and with plugs off I am getting milky stuff shooting out of the plug holes. So can I say its flooded? How do I deflood?

 

[Dr Honda]

You say.... "even put one plug on, press start and the it turns alittle bit then stops turning, then it turns a bit then stops."

That's not low compression. That's no power to push past compression.

Now... the starter you put in... was it a factory starter, or a Chinese hunk of crap? Have you checked the condition of the battey? Are the cables clean and tight?

You can't guess about compression... you have to put a gauge in the engine, and check it. BUT... if the starter, or battery is weak... then you will get a low reading anyway.

 

[murjiim]

Well the starter my friend.got it not sure where but somewhere in Florida for 40 bucks.
When I took the old starter out and testes it...it spun just fine.
My batt is good..it charged all night and cables are good

What is this milky stuff coming out?
Is there a way to get all this out?
He says he knows.there is water in then engine last

 

[Shuntavi]

Some how you need to isolate the engine and find out what is dragging. Jump the battery from another source like a car or something. If it's dragging while doing that and the plugs are out then I would suspect a bearing issue with the crank shaft. It doesn't take much to rotate the engine without plugs in it. Running water through a 2 stroke isn't a good thing. If it's been leaking water into the combustion chamber it may have made it's way down to the crank bearings.

 

[Shuntavi]

get a compression tester.

And I agree with roy4481. If you own a two stroke anything then you need a compression tester.

 

[murjiim]

I do have a compression tester
I put it in and it would struggle to spin

U though I will fry something if I jump it from a car batt?

 

[RXz71]

It will sound weird with the plugs off.
you shouldn't have to jump it if you charged it all night. Start it with the charger on if anything at all.

 

[roy4481]

dont jump it at all! replace the battery if needed...

 

[Rotor13B]

I'll take "bad ground" for $200 Wink.

lol, j/k but that's where i'd look first. Clean pos and neg cables on both ends. Clean area where power and ground connect too and take a wire brush to the battery terminals. If the battery terminals look dull and grey you're not getting the best connection. Terminals will oxidize even when they are new on the shelf. I bet the original starter is still good.

 

[Dr Honda]

dont jump it at all! replace the battery if needed...

Exactly. Don't jump it.

If the battery is dead... charging it won't help. Do this... put a meter on the battery, and crank the engine. If the voltage drops below 11v... the battery is dead. If it stays above 11v... then the $40 starter is junk. I have yet seen an aftermarket starter that was worth installing.

Back in the day... there was a company named Goky, and they made GREAT starters. But they were almost as expensive as the OEM's. As far as I know... they are out of Biz.


Normally, cranking the engine will get the water/oil/fuel out. But... if you don't have the power to spin it... then it's not going to come out. BUT... if it's been sitting with water in it... that engine is done.

 

[Shuntavi]

Jumping it a bad bad idea ? Sorry for the bad advice. I actually did this on my Speedster to make sure all the wiring I did worked before I spent 150 bucks on batteries. The batteries I got with speedster were only a year old but didn't have the amperage to crank the motor over.

 

[Dr Honda]

Jumping it a bad bad idea ? Sorry for the bad advice. I actually did this on my Speedster to make sure all the wiring I did worked before I spent 150 bucks on batteries. The batteries I got with speedster were only a year old but didn't have the amperage to crank the motor over.

Well... you got lucky. The seadoo MPEM's are fragile, and a known to burn-up when "Jump Started." Now... if you just have it hooked to a second battery... that's normally OK... but if you jump it from a running vehicle... then that is EXTRA bad. (or cranking while hooked to a charger)

 

[JCzGTX]

I do have a compression tester
I put it in and it would struggle to spin

U though I will fry something if I jump it from a car batt?

Do Not jump your ski off a car, if you have a car battery that is 12-volt not hooked up to a car.
If your compression was low, then engine would turn over even easier.
Even if you buy a brand new battery, trickle charge it over night. Most of the new batteries (around my area anyway) are no longer coming off the shelf fully charged.

 

[Shuntavi]

Oh ok. That explains some then. I cut out the mpem and re wired it. So Im not worried about that but I will not recommend it to the masses. Thanks. For the record though the car wasn't running.