Hey guys, I've been fiddling around with this for a little bit and I am ready to eat my shame and ask for some direction.
My 720 XP was running great all day a couple of weeks ago. I handed it off to my cousin and after about an hour of thinking "well something has definitely gone wrong", I see him getting towed into the dock. When he arrives he informs me that it just stopped and wouldn't start back up even though he cranked and cranked on it.
My first question to him was to see if he made sure to turn the bilge on every couple of minutes during the tow. He said he did. My second question was what happened. As a non-mechanically inclined person, his explanation was little to no help. Simply it died than wouldn't start again. He had no info on what happened beforehand.
With that, I went ahead and put a rope on the front loop then drug it over to the ramp and put it on the trailer. It was a solid week later until I had the opportunity to get into it and see what was going on.
When I did get that chance I discovered that the crank would spin about 1/4th of a turn then lock up going either way. My thought now is that it got hydro locked from the tow. At the time I did not know you were supposed to pinch off the waterline, but it wouldn't have mattered either way as he was the one on the ski. So I went ahead and sprayed some oil down the cylinder then let it sit overnight. The next morning I grabbed the PTO with a chain wrench and forced it to spin. This took very little effort it was not as if I was having to put a ton of torque into the PTO to unlock it, but just a slight amount of constant pressure followed by a pop and the thing was free spinning again.
At this point, in my mind, the most logical thing to do was to a compression test. I did so. 130 on the PTO side 60 on the mag side (UHG! what a forceful facepalm came next). -As a disclaimer before you guys jump all over me about it. I live in Colorado. 130 is the HIGHEST compression test I have ever pulled on either cylinder due to the altitude even when the motor was brand new.
So my questions following this completely uninspiring and disappointing story:
1: I have read on a few threads that following a hydro lock there is some potential that you can get it back on the water and run it at WOT for 20-30 minutes. This may or may not clear the water and allow the piston ring to re-seat to the cylinder. Is there any truth to this? In the garage, I am able to get the thing to start with the choke on, but it will not stay on for very long. I am assuming if I was at the water I could probably get it to run at WOT, but is this just going to hurt my motor more?
2: This motor was bored and honed +3mm. Am I able to get it re-sleeved and bored to fit my current pistons? Do I need to find a set of new jugs? do I need to buy a new set of pistons?
Just hoping there is a way to fix this thing without an entire top end rebuild. Let me know what you guys think and try to take it easy on me, my button is already pretty hurt!
My 720 XP was running great all day a couple of weeks ago. I handed it off to my cousin and after about an hour of thinking "well something has definitely gone wrong", I see him getting towed into the dock. When he arrives he informs me that it just stopped and wouldn't start back up even though he cranked and cranked on it.
My first question to him was to see if he made sure to turn the bilge on every couple of minutes during the tow. He said he did. My second question was what happened. As a non-mechanically inclined person, his explanation was little to no help. Simply it died than wouldn't start again. He had no info on what happened beforehand.
With that, I went ahead and put a rope on the front loop then drug it over to the ramp and put it on the trailer. It was a solid week later until I had the opportunity to get into it and see what was going on.
When I did get that chance I discovered that the crank would spin about 1/4th of a turn then lock up going either way. My thought now is that it got hydro locked from the tow. At the time I did not know you were supposed to pinch off the waterline, but it wouldn't have mattered either way as he was the one on the ski. So I went ahead and sprayed some oil down the cylinder then let it sit overnight. The next morning I grabbed the PTO with a chain wrench and forced it to spin. This took very little effort it was not as if I was having to put a ton of torque into the PTO to unlock it, but just a slight amount of constant pressure followed by a pop and the thing was free spinning again.
At this point, in my mind, the most logical thing to do was to a compression test. I did so. 130 on the PTO side 60 on the mag side (UHG! what a forceful facepalm came next). -As a disclaimer before you guys jump all over me about it. I live in Colorado. 130 is the HIGHEST compression test I have ever pulled on either cylinder due to the altitude even when the motor was brand new.
So my questions following this completely uninspiring and disappointing story:
1: I have read on a few threads that following a hydro lock there is some potential that you can get it back on the water and run it at WOT for 20-30 minutes. This may or may not clear the water and allow the piston ring to re-seat to the cylinder. Is there any truth to this? In the garage, I am able to get the thing to start with the choke on, but it will not stay on for very long. I am assuming if I was at the water I could probably get it to run at WOT, but is this just going to hurt my motor more?
2: This motor was bored and honed +3mm. Am I able to get it re-sleeved and bored to fit my current pistons? Do I need to find a set of new jugs? do I need to buy a new set of pistons?
Just hoping there is a way to fix this thing without an entire top end rebuild. Let me know what you guys think and try to take it easy on me, my button is already pretty hurt!
