Sportster-2001-951C-Stock
Well-Known Member
Umm, how about "seafoaming" that thing, or something like that?
Hard to re-start 4tec
- Thread starter 68ragtop
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68ragtop
Well-Known Member
Oddly, I have an unopened can of that stuff in the shop. Never used it before. When the starter gets here, I will see if anything changes, & if it doesn't I'll have to try something that can break down carbon & run it. I know seafoam is a no-no for 2 strokes because it can break down the oil, but I would assume its safe on a 4-stroke. Otherwise I guess I 'll pull the head.
Here is the video of the carbon on one of the pistons. The file is large (17Mb) & the player on my computer (macbook) keeps re-starting the video so its nearly impossible to watch. I uploaded it the other day, but when it wouldn't play I didn't bother posting. Nothing special about it, just oily deposited carbon. But maybe excessive for these engines? Not sure if its enough to raise the compression, or cause preigntion. But, probably not typical either.
http://www.automationsystems.ws/misc/4tec-piston.mov
Here is the video of the carbon on one of the pistons. The file is large (17Mb) & the player on my computer (macbook) keeps re-starting the video so its nearly impossible to watch. I uploaded it the other day, but when it wouldn't play I didn't bother posting. Nothing special about it, just oily deposited carbon. But maybe excessive for these engines? Not sure if its enough to raise the compression, or cause preigntion. But, probably not typical either.
http://www.automationsystems.ws/misc/4tec-piston.mov
Sportster-2001-951C-Stock
Well-Known Member
Yeah man, I hate the idea of trying to pour something down the intake to break carbon lose. Will that carbon find it's way into the rings and between the cylinder and piston? I dunno, these motors may not be forgiving? Some of the old timers still talk about how they used to decarbon cylinders without tearing down. Honestly, I find the entire idea somewhat dubious.
For such a lean running engine, how does it grow so much carbon, burning some oil, maybe? Is an injector dripping fuel/ leaking, if so then why aren't there signs of soot on the plugs and maybe rough idle? Maybe it could use some decent oil and a few hours constant running to burn some carbon out over time, I dunno.
Too funny, everyone wants high compression performance then complaints occur when they get it, LOL, not that you're complaining, but it seems ironic.
For such a lean running engine, how does it grow so much carbon, burning some oil, maybe? Is an injector dripping fuel/ leaking, if so then why aren't there signs of soot on the plugs and maybe rough idle? Maybe it could use some decent oil and a few hours constant running to burn some carbon out over time, I dunno.
Too funny, everyone wants high compression performance then complaints occur when they get it, LOL, not that you're complaining, but it seems ironic.
68ragtop
Well-Known Member
Personally I love working on these skis, & enjoy trouble shooting them, as every skii I have, or had was in need of work. But when I run out of ideas & something has me as stumped as this one, the fun starts to go away. with only 60 hours on the clock, its possible this thing sat in a small lake & putted around most of the time. Really not sure of its complete history.
When I get the starter, I will try that first. If it its the problem, I will be confused why, unless its marginally weak, or has an intermitant problem that is temperature induced. While I hope that is the case, I find its probably very unlikely.
When I get the starter, I will try that first. If it its the problem, I will be confused why, unless its marginally weak, or has an intermitant problem that is temperature induced. While I hope that is the case, I find its probably very unlikely.
68ragtop
Well-Known Member
Finally Solved........ Long post
Finally, I have some new news. The problem is solved at last.:thumbsup:
It was indeed the starter. I replaced the starter this afternoon & ran it until it was hot. Turned over perfectly each & every time. While I am happy to have this dilemma solved, Nothing about the original starter showed signs of failure or fatigue. Pretty safe to say that the armature was overloaded during the early events with the flywheel & assumably seized jet pump.
The compression in this engine averages 187 per hole cold. When the engine nears the 195 degree mark the compression rises to 200PSI. +/- This 7% jump was just enough of an increase to be more than the starter could overcome. As far as the carbon build up, hopefully its from years of little to no use, & heavy winterizing oil. Dennis had a good point, & felt the ski could have been fogged each season through the throttle body, causing long term build up of oil in the manifold & that makes a lot of sense. But, as it turns out, the carbon had little to do with the hard starts, and to some degree had me looking down the wrong path, because of the abnormal amount that was visible.
Now, back the starter. When I brought the armature to a rebuilding shop, they told me it was fine. But, given the short time they spent on it, I didn't think they were very thorough. I am always wrenching on something in the shop, & I decided to purchase a used Growler. On my tests, both armatures checked out identically. No shorted windings, no open windings & each field produced 19 Amps of current. all the way around the commutator. So, as I installed the new starter, I was not very confident of finding any change at all. But, to my surprise, it was a complete change, & the problem was corrected.
Pretty safe to assume now , the windings got hot & they have since lost some of their ability to produce strong magnetic fields. But according to my tests on the growler, it should have been fine. Short of some sort of motor dynamometer, I am not sure how this could be tested any further.
Thanks for hanging in their with me.
Finally, I have some new news. The problem is solved at last.:thumbsup:
It was indeed the starter. I replaced the starter this afternoon & ran it until it was hot. Turned over perfectly each & every time. While I am happy to have this dilemma solved, Nothing about the original starter showed signs of failure or fatigue. Pretty safe to say that the armature was overloaded during the early events with the flywheel & assumably seized jet pump.
The compression in this engine averages 187 per hole cold. When the engine nears the 195 degree mark the compression rises to 200PSI. +/- This 7% jump was just enough of an increase to be more than the starter could overcome. As far as the carbon build up, hopefully its from years of little to no use, & heavy winterizing oil. Dennis had a good point, & felt the ski could have been fogged each season through the throttle body, causing long term build up of oil in the manifold & that makes a lot of sense. But, as it turns out, the carbon had little to do with the hard starts, and to some degree had me looking down the wrong path, because of the abnormal amount that was visible.
Now, back the starter. When I brought the armature to a rebuilding shop, they told me it was fine. But, given the short time they spent on it, I didn't think they were very thorough. I am always wrenching on something in the shop, & I decided to purchase a used Growler. On my tests, both armatures checked out identically. No shorted windings, no open windings & each field produced 19 Amps of current. all the way around the commutator. So, as I installed the new starter, I was not very confident of finding any change at all. But, to my surprise, it was a complete change, & the problem was corrected.
Pretty safe to assume now , the windings got hot & they have since lost some of their ability to produce strong magnetic fields. But according to my tests on the growler, it should have been fine. Short of some sort of motor dynamometer, I am not sure how this could be tested any further.
Thanks for hanging in their with me.
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Sportster-2001-951C-Stock
Well-Known Member
Finally, I have some new news. The problem is solved at last.:thumbsup:
It was indeed the starter. I replaced the starter this afternoon & ran it until it was hot. Turned over perfectly each & every time. While I am happy to have this dilemma solved, Nothing about the original starter showed signs of failure or fatigue. Pretty safe to say that the armature was overloaded during the early events with the flywheel & assumably seized jet pump.
The compression in this engine averages 187 per hole cold. When the engine nears the 195 degree mark the compression rises to 200PSI. +/- This 7% jump was just enough of an increase to be more than the starter could overcome. As far as the carbon build up, hopefully its from years of little to no use, & heavy winterizing oil. Dennis had a good point, & felt the ski could have been fogged each season through the throttle body, causing long term build up of oil in the manifold & that makes a lot of sense. But, as it turns out, the carbon had little to do with the hard starts, and to some degree had me looking down the wrong path, because of the abnormal amount that was visible.
Now, back the starter. When I brought the armature to a rebuilding shop, they told me it was fine. But, given the short time they spent on it, I didn't think they were very thorough. I am always wrenching on something in the shop, & I decided to purchase a used Growler. On my tests, both armatures checked out identically. No shorted windings, no open windings & each field produced 19 Amps of current. all the way around the commutator. So, as I installed the new starter, I was not very confident of finding any change at all. But, to my surprise, it was a complete change, & the problem was corrected.
Pretty safe to assume now , the windings got hot & they have since lost some of their ability to produce strong magnetic fields. But according to my tests on the growler, it should have been fine. Short of some sort of motor dynamometer, I am not sure how this could be tested any further.
Thanks for hanging in their with me.
Might be able to measure starter torque. Is this a permanent-magnet starter by any chance? Permanent magnets can be remagnitized, just as they can lose magnetism over time. I just assumed it was a series-wound starter.......
68ragtop
Well-Known Member
Didn't most seadoo's use permanent magnets in the housing? Cold be a magnet problem, I didn't consider that possibility. I have no problem tossing it in the garbage can & probably will. I just have a brain that doesn't know when its a good time to quit wondering.
Sportster-2001-951C-Stock
Well-Known Member
I've run across perm magnet starters before that had weak magnets, last one was on an antique caddy. Sent it off for a rebuild, they told me they remagnitized the magnets. It worked great.
dsteinmann
New Member
I had the same issue after a rebuild, wouldn't start warm. It Was a looses Positive on the starter
mkov608
Active Member
Great post! Glad you got if fixed.
Two things. 1. There is Seafoam, and Seafoam Spray. If you need to de-carbon your engine, use the seafoam spray. It comes with a special spray tube; follow the instructions on the can. I love the stuff because my car has a direct injection engine (no fuel over the intake valves), and carbon builds up fast on the intake valves. Put the Seafoam motor treatment in the gastank. When I de-carboned my Sea-Doo engine, I found the exhaust leak that was causing significant performance issues.
2. I checked my compression (’02 4-tec w/ 50 hrs) and was running 190-195 between the three cylinders, so I don’t think you have a carbon buildup issue. Consider this, as heat increases in the starter, so does electrical resistance. However, you experienced a drop in voltage which is indicative of an increase in current. More current = more heat. More heat = even more resistance … nasty cycle. Again, glad you got it fixed.
K
Two things. 1. There is Seafoam, and Seafoam Spray. If you need to de-carbon your engine, use the seafoam spray. It comes with a special spray tube; follow the instructions on the can. I love the stuff because my car has a direct injection engine (no fuel over the intake valves), and carbon builds up fast on the intake valves. Put the Seafoam motor treatment in the gastank. When I de-carboned my Sea-Doo engine, I found the exhaust leak that was causing significant performance issues.
2. I checked my compression (’02 4-tec w/ 50 hrs) and was running 190-195 between the three cylinders, so I don’t think you have a carbon buildup issue. Consider this, as heat increases in the starter, so does electrical resistance. However, you experienced a drop in voltage which is indicative of an increase in current. More current = more heat. More heat = even more resistance … nasty cycle. Again, glad you got it fixed.
K
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