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My 2002 Ski Nautique has been suffering for a couple of weeks. Why is it that 2 or 3 items always pop up during diagnosis of a boat problem?
This time I narrowed the hole shot issue to a bad fuel pump, water in fuel and leaky muffler. So it turns out the high pressure fuel pump was weak, the muffler had a small leak and was broken inside. A broken muffler tube (baffle) caused back pressure and robbed engine horsepower. Details follow for those with a similar issue.
Problem was a loss of hole shot while starting a slalom skier – maybe 50% power. Also, twice, I heard a clunk sound when put boat in gear - like it tapped an underwater branch.
Fuel pressure check was good with key-on engine off. Fuel pressure was slightly low (31 vs 35 psi) at 2,000 rpm in neutral. I got some good tips on this discussion. http://www.planetnautique.com/vb5/fo...sure-test-gt40
During the high pressure fuel pump change, I noticed a bit of water in the glass jar of fuel that was drained from FCC. I think this was a red herring and the humid atmosphere added more water to the jar while the fuel sat during the day.
During the initial power loss diagnosis, I found a small hole in the top of the Centek Hull Hugger muffler. A small stream of water was shooting from an area in the muffler that was patched 2 years ago with JB Weld.
First steps, install a new high pressure fuel pump, add fresh gas with SeaFoam, and put more JB Weld on the muffler hole. Now the boat runs much better - but only 80% power or so. Not happy, but at least the boat works for lighter skiers.
I pulled the muffler Centek 1601139 hull hugger muffler. 2002 Ski Nautiques have a bat-wing trunk, I removed the floor from the trunk to access the muffler stern exhaust clamps. You don’t need to remove the fuel tank that sits over the muffler. Some guys remove the exhaust risers when replacing the muffler. You can decide what is easier, but it’s not necessary. If your risers leak then it is a good time to replace the gaskets
Loosen all the cable clamps. Start at the back of the exhaust risers; continue down to the exhaust flap while skipping the ones at the back of the muffler.
Use a radiator hose tool and squirts of WD-40 to loosen the rubber hoses from the exhaust riser and both ends of the 2 fiberglass exhaust tubes. The radiator hose tool is similar to an ice pick bent around a piece of ½” square bar.
The 2002 fuel tank sits over the rear muffler clamps but you don’t need to remove those clamps until you pull the muffler from the boat.
To remove the muffler: Push the hoses away from the muffler toward the bow as far as you can. Next bend/crimp the flexible hoses between the fiberglass tubes and the muffler. Use some man-strength and wrestle them off. If you remove the manifold risers then the hose wrestling is eliminated. Removing risers takes more time and money. My gaskets are only a year old, removing and replacing them might add 45 minutes or more and $25 to the job.
Once the flexible hoses are free from the bow side of the muffler, pull the muffler along with the hose that was disconnected from the stern flapper. High five your dog and drink a beer.
Clean the embarrassing bilge gunk. Clean and paint the fiberglass exhaust tubes. Inspection showed areas where the bad muffler was rubbing the hull. A couple of thin spots in the fiberglass, but no holes had rubbed through. There are 2 neoprene pads under the muffler, they were loose but in place. Cleaned the pads up and glued them back down. Added some neoprene from old ski binding to cushion the muffler bottom between the 2 OEM strips. Gorilla Glue was my choice but there may be better options.
By now you should now how everything goes back together. Connect the hose to the back of the muffler. Bandage your hand that was cut by tail of hose clamp on raw water intake. Clean up some blood. Position the muffler and connect the exit hose to the exhaust flap. Use liquid dish soap to lube the hoses onto the hard points from front of muffler to the risers. Connect it up and check for leaks.
Bad muffler diagnosis: Beside the 2 clunks and the water leak noted above – the muffler would rattle when boat was in gear. The worse the rattle noise corresponded to worse engine performance. With the boat’s floorboard removed, you could see the bad muffler pillow up 3/8” when the engine started.
Bad muffler internals: Without a good muffler for comparison it was hard to tell what was going on with the bad muffler. The tube connecting the front compartment to the rear compartment was broken and pushed toward the stern and blocked water flow. Bad muffler tube was about an inch showing in front chamber. The good muffler tube was a couple of inches showing in the front chamber with a hole for water to pass to the 2nd chamber.
The muffler separated between the top of the muffler and its internal bulkhead. It appears the exhaust water was blocked by the internal tube collapse and forced water/gas over the separation gap between the bulkhead and the outer muffler.
This time I narrowed the hole shot issue to a bad fuel pump, water in fuel and leaky muffler. So it turns out the high pressure fuel pump was weak, the muffler had a small leak and was broken inside. A broken muffler tube (baffle) caused back pressure and robbed engine horsepower. Details follow for those with a similar issue.
Problem was a loss of hole shot while starting a slalom skier – maybe 50% power. Also, twice, I heard a clunk sound when put boat in gear - like it tapped an underwater branch.
Fuel pressure check was good with key-on engine off. Fuel pressure was slightly low (31 vs 35 psi) at 2,000 rpm in neutral. I got some good tips on this discussion. http://www.planetnautique.com/vb5/fo...sure-test-gt40
During the high pressure fuel pump change, I noticed a bit of water in the glass jar of fuel that was drained from FCC. I think this was a red herring and the humid atmosphere added more water to the jar while the fuel sat during the day.
During the initial power loss diagnosis, I found a small hole in the top of the Centek Hull Hugger muffler. A small stream of water was shooting from an area in the muffler that was patched 2 years ago with JB Weld.
First steps, install a new high pressure fuel pump, add fresh gas with SeaFoam, and put more JB Weld on the muffler hole. Now the boat runs much better - but only 80% power or so. Not happy, but at least the boat works for lighter skiers.
I pulled the muffler Centek 1601139 hull hugger muffler. 2002 Ski Nautiques have a bat-wing trunk, I removed the floor from the trunk to access the muffler stern exhaust clamps. You don’t need to remove the fuel tank that sits over the muffler. Some guys remove the exhaust risers when replacing the muffler. You can decide what is easier, but it’s not necessary. If your risers leak then it is a good time to replace the gaskets
Loosen all the cable clamps. Start at the back of the exhaust risers; continue down to the exhaust flap while skipping the ones at the back of the muffler.
Use a radiator hose tool and squirts of WD-40 to loosen the rubber hoses from the exhaust riser and both ends of the 2 fiberglass exhaust tubes. The radiator hose tool is similar to an ice pick bent around a piece of ½” square bar.
The 2002 fuel tank sits over the rear muffler clamps but you don’t need to remove those clamps until you pull the muffler from the boat.
To remove the muffler: Push the hoses away from the muffler toward the bow as far as you can. Next bend/crimp the flexible hoses between the fiberglass tubes and the muffler. Use some man-strength and wrestle them off. If you remove the manifold risers then the hose wrestling is eliminated. Removing risers takes more time and money. My gaskets are only a year old, removing and replacing them might add 45 minutes or more and $25 to the job.
Once the flexible hoses are free from the bow side of the muffler, pull the muffler along with the hose that was disconnected from the stern flapper. High five your dog and drink a beer.
Clean the embarrassing bilge gunk. Clean and paint the fiberglass exhaust tubes. Inspection showed areas where the bad muffler was rubbing the hull. A couple of thin spots in the fiberglass, but no holes had rubbed through. There are 2 neoprene pads under the muffler, they were loose but in place. Cleaned the pads up and glued them back down. Added some neoprene from old ski binding to cushion the muffler bottom between the 2 OEM strips. Gorilla Glue was my choice but there may be better options.
By now you should now how everything goes back together. Connect the hose to the back of the muffler. Bandage your hand that was cut by tail of hose clamp on raw water intake. Clean up some blood. Position the muffler and connect the exit hose to the exhaust flap. Use liquid dish soap to lube the hoses onto the hard points from front of muffler to the risers. Connect it up and check for leaks.
Bad muffler diagnosis: Beside the 2 clunks and the water leak noted above – the muffler would rattle when boat was in gear. The worse the rattle noise corresponded to worse engine performance. With the boat’s floorboard removed, you could see the bad muffler pillow up 3/8” when the engine started.
Bad muffler internals: Without a good muffler for comparison it was hard to tell what was going on with the bad muffler. The tube connecting the front compartment to the rear compartment was broken and pushed toward the stern and blocked water flow. Bad muffler tube was about an inch showing in front chamber. The good muffler tube was a couple of inches showing in the front chamber with a hole for water to pass to the 2nd chamber.
The muffler separated between the top of the muffler and its internal bulkhead. It appears the exhaust water was blocked by the internal tube collapse and forced water/gas over the separation gap between the bulkhead and the outer muffler.