***Sorry, I realize this is the PWC section, and I did post to the boat section, but I think this is more a driveline problem than hull problem.***
This one has been driving me insane. The boat is a Sea-Doo Sportster 155hp with about 200 hours. When I purchased it, the pump was in pretty rough shape, so I sent it out to Impros and had it rebuilt with a dual impeller setup. I had the ECU tuned to match the new pump by Racelab. It was calibrated for my altitude (5500 asl) as well as more performance, 8500 rpm redline. First few times on the water, the boat screamed, got up on plane super quick, and was able to reach 50mph + at 8500. Somewhere around the third or fourth day at this level, as I was going along at full throttle, I experienced a vibration through the hull. I backed it off and brought it in. I noticed one of the pieces of the intake grate were missing. I don't know if it was like that before or not, but I just replaced the intake grate with an all metal type (Worx I think) and brought it back out. From that moment on, every time I hit 6300-6500 rpm, the vibration comes back. If I push through, the boat will continue to about 7000 rpm, but will not accelerate further. Now the boat runs about 40mph at 6800-7000 rpm. If I do cross 6300-6500rpm and it begins vibrating, I have to back it off to about 4500 or less for the vibration to go away completely and seemingly suddenly. Once it's gone, I can run it all the way back up to 6300-6500 without vibration.
What I've since tried and replaced...
I sent the pump back to impros just to make sure that if a piece of the grate went through, there was no damage. It is perfect.
I replaced spark plugs, coil packs, fuel injectors, fuel pump, fuel pressure regulator, fuel filters.
I Installed a fuel pressure gauge to ensure proper pressure, I have Candoo Pro, and found no codes.
I replaced the carbon seal and bellows. I realigned the engine. I replaced the battery.
I changed the oil and filled to the proper level. I had the water box gutted professionally to rule out a restriction there, installed an exhaust manifold spacer,
installed an air filter in place of the air box. I see no evidence of exhaust leak and have run without the engine cover to rule out. I replaced the air box with a cone filter to rule out a restriction there. I removed and ran without an intake grate to rule out the new intake grate. I checked the throttle cable to ensure the throttle body opens fully at full throttle. I calibrated the TPS to ensure accuracy. I made sure the reverse bucket stows properly and tightly when in forward thrust. I drained and filled the fuel tank with known fresh fuel. I performed a compression test and found 150psi nearly dead even across all three cylinders which is within spec for sea level, adjusted for altitude puts it well over 170psi.
I am open to any and all ideas, theories, and suggestions. I'm going to post this on a few other forums as well, so I apologize for any overlap. Below is a photo of a runtime rpm from Candoo to show that at one point I was actually making over 8150 rpm, and not for an insignificant amount of time (50 minutes total).
Sorry for the insane layout of this, and thank you all in advance.
This one has been driving me insane. The boat is a Sea-Doo Sportster 155hp with about 200 hours. When I purchased it, the pump was in pretty rough shape, so I sent it out to Impros and had it rebuilt with a dual impeller setup. I had the ECU tuned to match the new pump by Racelab. It was calibrated for my altitude (5500 asl) as well as more performance, 8500 rpm redline. First few times on the water, the boat screamed, got up on plane super quick, and was able to reach 50mph + at 8500. Somewhere around the third or fourth day at this level, as I was going along at full throttle, I experienced a vibration through the hull. I backed it off and brought it in. I noticed one of the pieces of the intake grate were missing. I don't know if it was like that before or not, but I just replaced the intake grate with an all metal type (Worx I think) and brought it back out. From that moment on, every time I hit 6300-6500 rpm, the vibration comes back. If I push through, the boat will continue to about 7000 rpm, but will not accelerate further. Now the boat runs about 40mph at 6800-7000 rpm. If I do cross 6300-6500rpm and it begins vibrating, I have to back it off to about 4500 or less for the vibration to go away completely and seemingly suddenly. Once it's gone, I can run it all the way back up to 6300-6500 without vibration.
What I've since tried and replaced...
I sent the pump back to impros just to make sure that if a piece of the grate went through, there was no damage. It is perfect.
I replaced spark plugs, coil packs, fuel injectors, fuel pump, fuel pressure regulator, fuel filters.
I Installed a fuel pressure gauge to ensure proper pressure, I have Candoo Pro, and found no codes.
I replaced the carbon seal and bellows. I realigned the engine. I replaced the battery.
I changed the oil and filled to the proper level. I had the water box gutted professionally to rule out a restriction there, installed an exhaust manifold spacer,
installed an air filter in place of the air box. I see no evidence of exhaust leak and have run without the engine cover to rule out. I replaced the air box with a cone filter to rule out a restriction there. I removed and ran without an intake grate to rule out the new intake grate. I checked the throttle cable to ensure the throttle body opens fully at full throttle. I calibrated the TPS to ensure accuracy. I made sure the reverse bucket stows properly and tightly when in forward thrust. I drained and filled the fuel tank with known fresh fuel. I performed a compression test and found 150psi nearly dead even across all three cylinders which is within spec for sea level, adjusted for altitude puts it well over 170psi.
I am open to any and all ideas, theories, and suggestions. I'm going to post this on a few other forums as well, so I apologize for any overlap. Below is a photo of a runtime rpm from Candoo to show that at one point I was actually making over 8150 rpm, and not for an insignificant amount of time (50 minutes total).
Sorry for the insane layout of this, and thank you all in advance.
