-
This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.
SPX locking up then starting back
- Thread starter SPXblake
- Start date
DaddyLoafin
Active Member
My 98 spx did something similar right before it melted the pto piston. Not saying this is 100% what's happening but saying you might want to be careful
SPXblake
Member
O if I’m not mistaken the pto is the rear? Either way the rear cylinder is usually hotter than the front one
SPXblake
Member
I don’t think it’s the pump as we re did the entire pump
Was it locking up before you did the pump?
DaddyLoafin
Active Member
you are correct.
SPXblake
Member
No but before I did the pump it had a different motor in it
Ah, no leads there then, I’m sure it has been mentioned but an engine locking up is very unusual and most likely damaging. It’s been mentioned here but I would have to think it’s running lean and heating up, causing it to essentially cold seize. Do you know if it has forged or cast pistons? Good flow coming out the pisser?
I could definitely be using the wrong terminology but on snowmobile it’s when the piston expands to much or to fast compared to the cylinder. If you use a forged piston in a snowmobile you have to warm it up for a minute or so, let it sit for another few minutes for the heat to transfer evenly and then warm up again before heading out
From Group K. One very skilled engine guru's opinion...
Fables and Untruths: Cold Seizure – this is by far the most over used “seizure scapegoat”. It some how implies that the rider ran his engine in a way that caused the failure. At least 95% if the “so called” cold seized engines that I’ve seen have had a very apparent problem elsewhere in the engine that the original technician failed to see. Telling a customer that he cold seized the engine is an easy way for a mechanic to immediately reverse the guilt and the responsibility.
If a freshly bored engine or a high performance engine were started from stone cold, and then run hard at high rpm within 30 seconds of the start up, it could very likely experience a true cold seizure. This happens because the aluminum piston would experience a radically faster rate of expansion in that 30 seconds than the cylinder does. The reason for this difference in expansion rate is two fold.
First and foremost, the internal temperatures that the piston crown is exposed to at full load are on the order of 800°F – 1100°F. The gases passing through the exhaust manifold ports is also in this 800° -1100°F temperature range. The expansion rate caused by these temperatures is usually not a problem when the water entering the exhaust manifold is being preheated by the very hot exhaust port passages. However in the first 30 – 50 seconds of operation, these internal exhaust ports have not yet absorbed the heat that’s needed to properly pre heat the cold incoming water. During the first 30 operating seconds, this cold incoming water will briefly maintain the water jacket around the cylinder at “stone cold diameter” while the piston is becoming “full temperature diameter”. On engines with properly sized pistons, the difference in these diameters becomes much more than even the best oils can withstand. Any engine that has been warmed up for 60 seconds or longer, would be virtually incapable of a “cold seizure”
Fables and Untruths: Cold Seizure – this is by far the most over used “seizure scapegoat”. It some how implies that the rider ran his engine in a way that caused the failure. At least 95% if the “so called” cold seized engines that I’ve seen have had a very apparent problem elsewhere in the engine that the original technician failed to see. Telling a customer that he cold seized the engine is an easy way for a mechanic to immediately reverse the guilt and the responsibility.
If a freshly bored engine or a high performance engine were started from stone cold, and then run hard at high rpm within 30 seconds of the start up, it could very likely experience a true cold seizure. This happens because the aluminum piston would experience a radically faster rate of expansion in that 30 seconds than the cylinder does. The reason for this difference in expansion rate is two fold.
First and foremost, the internal temperatures that the piston crown is exposed to at full load are on the order of 800°F – 1100°F. The gases passing through the exhaust manifold ports is also in this 800° -1100°F temperature range. The expansion rate caused by these temperatures is usually not a problem when the water entering the exhaust manifold is being preheated by the very hot exhaust port passages. However in the first 30 – 50 seconds of operation, these internal exhaust ports have not yet absorbed the heat that’s needed to properly pre heat the cold incoming water. During the first 30 operating seconds, this cold incoming water will briefly maintain the water jacket around the cylinder at “stone cold diameter” while the piston is becoming “full temperature diameter”. On engines with properly sized pistons, the difference in these diameters becomes much more than even the best oils can withstand. Any engine that has been warmed up for 60 seconds or longer, would be virtually incapable of a “cold seizure”
I agree, cold seizure was the wrong term in this circumstance. Cold seizures are common in snowmobiles, especially with forged pistons. Riding in -22 Fahrenheit, if your to hop on and take off without a proper warm up your asking for problems. Not an issue with Seadoo’s. Would lean seize be the appropriate term here?
I have seen it happen only once, when a shop did not set the clearance correctly for forged Wiseco pistons. Never on cast pistons.
I don’t like them, I’m sure they have there place but as a rec rider I will always use cast
SPXblake
Member
Not sure about forged or cast but there is a good flow from the pisser so my cooling system checks out. One thing that have something to do with the cut out is my mpem went bad. Could that lean condition lead to my oil pump going bad?
Lean condition is not going to damage the oil pump, is it cutting out or locking up? I’ve been under the impression that the engine is locking up?
SPXblake
Member
Well it cuts out then locks up then unlocks after pressing the button a loy
