pete63
Active Member
any water in the bilge? check the carbon seal for damage and top hat connection on the shaft
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Max speed 38 mph, cavitation?
- Thread starter Wseadoo180
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any water in the bilge? check the carbon seal for damage and top hat connection on the shaft
Wseadoo180
Member
No water at all - the last trip she was in the water for 48 hours and not a drop of water was in there.
I also checked the riding plate - found an online tutorial the tilts the boat/jet ski down at the front, and then fill the riding plate area with a few cups of water and wait to see any leaks - no leaks in my case.
Re the carbon seal - checked and everything there looks brand new - somebody suggested I can pull the shaft, grease around the carbon seal, and put it back in. If there is indeed a problem there, it would show up right away (grease will act as a temp seal).
To be honest I am no longer sure if this is "Cavitation" as when I am by myself and give it gas, it takes off nicely, with alot of people it takes time to plane. But always no matter what, top speed doesn't go above 39/40.
pete63
Active Member
ok
cavitation is from start under load and doesnt get up to speed. better check super charger/ coils / injectors/ plugs
anthonymsaad
Active Member
Not sure if this is ruled out, but has the pitch on your impeller been checked? Everything seems fine. You should be getting a max RPM at around 7300 and if wear rings are fine, just could be impeller pitch issues. If there isn't any change in top speed between little weight to several people, then impeller could be pitched for more thrust at low end, thereby improving performance at low speeds but causing top end to be reduced. I have twin SC engines on mine and just to clear things up, with a 155hp engine, you are naturally aspirated and don't have a super charger to worry about, which reduces possibility of clutch slippage being a cause. Also, if it were supercharged, max RPMs are raised to 8000.
Regards to cavitation, it doesn't sound like that is your issue. You'd notice it getting worse as the leading edge of your impeller would be wearing down a bit, which I didn't notice in your pictures. I used to have a single engine jet boat and noticed that top speed didn't vary too much between myself and 4 other people. Would go from 43mph to 40mph. But that was with a Yamaha AR190, so it had a naturally aspirated 180hp motor. Comparable to your boat, but a bit more power and bit more weight as well. That said, I am aware some boat test reviews indicate higher speeds, different RPMs, and what not, but most of the time, that isn't realistic. Looking up my boat, I found large discrepancies between sites and their "results" they found. Some of the technical information about their test boat doesn't even match up with real boats.
For a boat like yours, I honestly wouldn't expect a top end speed higher than a bit above 40mph. I have a neighbor that, with his '06 speedster 200, with 2x 155hp motors for a total of 310hp, would get up 52mph by himself on calm water, and he does all the service and maintenance himself. Unlike a car, where a 100hp different means noticeable top end speed difference, boats are different, since boats deal with water drag. Compared to your boat, he's getting 12mph higher top end but is doubling your power. Even on my 210 challenger, with a few hundred more pounds of weight than his, for me to get my top end of 53mph, I have to have twin supercharged engines producing 430hp to get there. I doubt your boat would manage 47mph with a single 155hp engine. Those results mentioned earlier seem to be more of an accordance with a twin engine setup, with each engine N/A and producing 155hp each.
Hopefully someone will correct me if I'm wrong. I am assuming you have a single engine, 19'-20ft boat. If your boat is smaller, than I would expect maybe top end to be 45mph. Wish you the best of luck and if you have any question, would be glad to help.
Regards to cavitation, it doesn't sound like that is your issue. You'd notice it getting worse as the leading edge of your impeller would be wearing down a bit, which I didn't notice in your pictures. I used to have a single engine jet boat and noticed that top speed didn't vary too much between myself and 4 other people. Would go from 43mph to 40mph. But that was with a Yamaha AR190, so it had a naturally aspirated 180hp motor. Comparable to your boat, but a bit more power and bit more weight as well. That said, I am aware some boat test reviews indicate higher speeds, different RPMs, and what not, but most of the time, that isn't realistic. Looking up my boat, I found large discrepancies between sites and their "results" they found. Some of the technical information about their test boat doesn't even match up with real boats.
For a boat like yours, I honestly wouldn't expect a top end speed higher than a bit above 40mph. I have a neighbor that, with his '06 speedster 200, with 2x 155hp motors for a total of 310hp, would get up 52mph by himself on calm water, and he does all the service and maintenance himself. Unlike a car, where a 100hp different means noticeable top end speed difference, boats are different, since boats deal with water drag. Compared to your boat, he's getting 12mph higher top end but is doubling your power. Even on my 210 challenger, with a few hundred more pounds of weight than his, for me to get my top end of 53mph, I have to have twin supercharged engines producing 430hp to get there. I doubt your boat would manage 47mph with a single 155hp engine. Those results mentioned earlier seem to be more of an accordance with a twin engine setup, with each engine N/A and producing 155hp each.
Hopefully someone will correct me if I'm wrong. I am assuming you have a single engine, 19'-20ft boat. If your boat is smaller, than I would expect maybe top end to be 45mph. Wish you the best of luck and if you have any question, would be glad to help.
He has a 15' sportster. Should be mid-upper 40's for mph with 155hp motor. My old 215 motor was mid 50's with the same hull.
anthonymsaad
Active Member
My apologies, you're definitely correct. I also apologize for the length of this post, tired my best to be through and, if I made any mistakes, I would appreciate being corrected. To summarize what I wrote, I pretty much think wellysm should check his throttle cable.
For the last few days, I spent quite a bit of time trying to figure this out. I was looking for test reviews of the boat, where they posted the boat's speed at their corresponding RPMs and came across this discussion.
http://www.greenhulk.net/forums/showthread.php?t=136885&page=2
Essentially, someone else was having similar performance issues as wellysm, such as lower than expected top speed ( 38-40mph), along with other guys confirming top speed, with a 155hp engine, around upper 40's and lower 50's. They initially thought the impeller or wear ring was an issue, but for another person with similar performance issues, the issue was the throttle cable. The throttle cable got stretched out and needed to be adjusted to actually open the throttle.
In wellysm's case, it could possibly be the throttle cable, if he hasn't checked that yet. Just to make sure, I tried my best to verify the part number on the impeller and make sure it was from Seadoo, as well as know what the pitch is.
( http://staging.sea-doo.cust.shopatron.com/product/962977/267000673/_/Impeller# )
Going off the impeller being properly pitched, the likelihood the issue is stemming from a higher pitched impeller putting too much load and the engine and reducing RPM, I shifted focus to when willysm stated that he's getting a 1400 RPM difference when going from half throttle, at 5500 RPM, to WOT and maxing out at 6900 RPM, when his RPM limiter should be at 7300. With the probability that this reduce max RPM is caused by improper impeller pitch, a loose cable throttle would be the most likely cause to reduce max RPM.
Additionally, as wellysm stated that, at 5500 RPM, he's going about 30mph, I am doing about the same speed at nearly the same RPM, as well as other boat reviews indicated. Because of that, I am not lead to believe anything is mechanically wrong with his engine that would be restricting his performance, as it is relatively linear and normal for his boat to be doing 30mph at 5500 rpm. Passed that, doubt a mechanical issue would consistently occur at higher RPMs, except throttle cable.
For the last few days, I spent quite a bit of time trying to figure this out. I was looking for test reviews of the boat, where they posted the boat's speed at their corresponding RPMs and came across this discussion.
http://www.greenhulk.net/forums/showthread.php?t=136885&page=2
Essentially, someone else was having similar performance issues as wellysm, such as lower than expected top speed ( 38-40mph), along with other guys confirming top speed, with a 155hp engine, around upper 40's and lower 50's. They initially thought the impeller or wear ring was an issue, but for another person with similar performance issues, the issue was the throttle cable. The throttle cable got stretched out and needed to be adjusted to actually open the throttle.
In wellysm's case, it could possibly be the throttle cable, if he hasn't checked that yet. Just to make sure, I tried my best to verify the part number on the impeller and make sure it was from Seadoo, as well as know what the pitch is.
( http://staging.sea-doo.cust.shopatron.com/product/962977/267000673/_/Impeller# )
Going off the impeller being properly pitched, the likelihood the issue is stemming from a higher pitched impeller putting too much load and the engine and reducing RPM, I shifted focus to when willysm stated that he's getting a 1400 RPM difference when going from half throttle, at 5500 RPM, to WOT and maxing out at 6900 RPM, when his RPM limiter should be at 7300. With the probability that this reduce max RPM is caused by improper impeller pitch, a loose cable throttle would be the most likely cause to reduce max RPM.
Additionally, as wellysm stated that, at 5500 RPM, he's going about 30mph, I am doing about the same speed at nearly the same RPM, as well as other boat reviews indicated. Because of that, I am not lead to believe anything is mechanically wrong with his engine that would be restricting his performance, as it is relatively linear and normal for his boat to be doing 30mph at 5500 rpm. Passed that, doubt a mechanical issue would consistently occur at higher RPMs, except throttle cable.
Wseadoo180
Member
Hello Lumps,
This was the last thing I checked - Please check out my last post on the previous page. That is the method I tested for the leak - seems all good.
Anthonymsaad, thank you for the thorough reply, and taking your time to try to help me out! I really appreciate the informative post you wrote
Regarding the impeller - when I took the housing to the seadoo dealership, they checked it and verified it is stock impeller
Regarding the throttle cable, it was the first thing I checked and was hoping it would be it, however at full WOT the cable turns the throttle knob to its max position
To be honest I am starting to regret the hundreds of hours I put into this boat to bring it back into a clean mechanical and physical condition. Not being able to figure this out has been frustrating. I am tempted to give in and bring it to the dealership to let them give it a shot.... however when I was there last they were as puzzled as I was and mentioned everything that I had already tried.
anthonymsaad
Active Member
wellysm, you're welcome and sorry it didn't help. I hate that you can't fully enjoy your boat. I've spent 2 months without mine due to a weird electrical ECM issue thats occurring on just one of my 2 engines that non of the dealership techs have ever seen before. It already fried one brand new ECM and hopefully it won't fry the second new one. That aside, I understand your frustration and your issue is on my mind and trying to figure out what could be causing it. Worst case, bringing it in to a dealership may be the best way of resolving it quickly without spending so much time and money by yourself.
I've been looking around and trying to go through everything. One thing that you could do would be to do a compression test on your engine, if you haven't already. If it has low compression, or only one cylinder having low pressure, your engine won't be able to make full power. That would translate into less torque/hp to rotate your impeller, possibly resulting in lower RPMs. Especially with these engines revving so high, I'm guessing compression on each cylinder become important at higher RPMs. Additionally, could be responsible for the rattling noise you stated earlier, when at idle. Now, I'm trying to find those issues that become more noticeable at higher RPMs and more subtle at lower RPMs. Checking cylinder compression, may potentially see if valves or seals are an issue. Doesn't seem like your fuel injectors are clogged. Although top speed is main issue, I'm focusing more on RPMs, since it should be hitting the rev limiter. Furthermore, with the ratio of speed to RPMs increasing exponentially, resolving the low RPMs would resolve top end speed.
I just checked the owners manual for your year of boat and noticed a difference in specs about your engine, compared to other boats. For other boats, like mine, max HP occurs at max RPM, where it hits the rev limiter. For yours, max HP occurs at 7300 RPMs, but your rev limiter is 7650 RPMs, which threw me off a bit. Technically, you should be hitting close to 7650 RPMs, making your situation odd.
If everything mechanical appears to be correct, engine is in great shape, which you seem to be doing an excellent job of, and only issue is low RPMs, you could swap the impeller for a lower pitched one. Switching should allow you hit the rev limiter. On top of that, looking at the pitch of the impeller that seems to be in your boat, it looks to be pitched higher than normal. Im finding that stock impeller pitch is around 11/19, where the part number impeller is showing a pitch of 10/21. Even if it is the case that you have a high pitched impeller, it shouldn't make that much of a change, unless it is relatively pitched greatly higher than stock.
I've been looking around and trying to go through everything. One thing that you could do would be to do a compression test on your engine, if you haven't already. If it has low compression, or only one cylinder having low pressure, your engine won't be able to make full power. That would translate into less torque/hp to rotate your impeller, possibly resulting in lower RPMs. Especially with these engines revving so high, I'm guessing compression on each cylinder become important at higher RPMs. Additionally, could be responsible for the rattling noise you stated earlier, when at idle. Now, I'm trying to find those issues that become more noticeable at higher RPMs and more subtle at lower RPMs. Checking cylinder compression, may potentially see if valves or seals are an issue. Doesn't seem like your fuel injectors are clogged. Although top speed is main issue, I'm focusing more on RPMs, since it should be hitting the rev limiter. Furthermore, with the ratio of speed to RPMs increasing exponentially, resolving the low RPMs would resolve top end speed.
I just checked the owners manual for your year of boat and noticed a difference in specs about your engine, compared to other boats. For other boats, like mine, max HP occurs at max RPM, where it hits the rev limiter. For yours, max HP occurs at 7300 RPMs, but your rev limiter is 7650 RPMs, which threw me off a bit. Technically, you should be hitting close to 7650 RPMs, making your situation odd.
If everything mechanical appears to be correct, engine is in great shape, which you seem to be doing an excellent job of, and only issue is low RPMs, you could swap the impeller for a lower pitched one. Switching should allow you hit the rev limiter. On top of that, looking at the pitch of the impeller that seems to be in your boat, it looks to be pitched higher than normal. Im finding that stock impeller pitch is around 11/19, where the part number impeller is showing a pitch of 10/21. Even if it is the case that you have a high pitched impeller, it shouldn't make that much of a change, unless it is relatively pitched greatly higher than stock.
Wseadoo180
Member
That is my biggest fear with these seadoos ... an ECM issue! They get costly pretty fast. Good luck with that I hope they solve the problem soon!
Re the impeller - I will double check. The dealership mechanics both looked at it and stated it looks to be OEM/checked the part number etc.
Re rattling at idle - I found out that this is normal, with the impeller and impeller shaft design, not enough pressure holding it back.
Re RPMs - initially I thought replacing the sparkplugs would solve it, but no it stayed the same - between 6800 - 7000... The other day I took the boots off, cleaned everything once again, put di-electric grease on the rubber/ceramic etc. But what I didn't do before was never cleaned where the sparkplug nipple inset into... i took some sand paper and cleaned in there very well. However, with the knowledge I have about electricity, I know this won't do much. The only thing that can be happening at higher RPMs the spark plugs are arcing ...but doubt it with all the precautions I did after I got the boat.
Lastly - compression test! I actually never got to do one - one time I was looking into it, and with the 4tec engine when I unplugged the spark plugs it wouldn't even turn it over... not sure how I would run a compression test ... unless I keep all sparkplugs plugged into but grounded on the engine body.
Wseadoo180
Member
Update :
After the spark plug cleaning (mentioned above)... And switching gas grade from 91 ethanol free to regular 89... My rpms went from 6800 to 7050/7100
Very interesting... Not sure if it's the ethanol or the cleaning I did for the plugs.... I read in another post that higher octane maybe the culprit
Either way... Top speed reached 41! Before my max was 39/40... This is with no one in the boat... And stays around 39/40 with an additional 350 lb of passages... Very strange
I will look around and see if there is a shop that can examine the pitch of my prop. Would love to get up to the 50mph mark
After the spark plug cleaning (mentioned above)... And switching gas grade from 91 ethanol free to regular 89... My rpms went from 6800 to 7050/7100
Very interesting... Not sure if it's the ethanol or the cleaning I did for the plugs.... I read in another post that higher octane maybe the culprit
Either way... Top speed reached 41! Before my max was 39/40... This is with no one in the boat... And stays around 39/40 with an additional 350 lb of passages... Very strange
I will look around and see if there is a shop that can examine the pitch of my prop. Would love to get up to the 50mph mark
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