vas
Well-known member
hi all,
seen Jeremy's williams jetrib guide and after 4 seasons of sorting out a now 20yo Avon jetrib, I decided to write down a maintenance to do (and how to) list of issues I had to address to keep a well maintained 20yo seawater jetrib in reasonable and reliable condition. Any corrections, additions, comments welcomed!
First of all, a couple of links that will help identify parts or understand how the thing works!
1999 Yamaha WAVE RUNNER XL700 (XL700X) OEM Parts, Flemington Yamaha [describes all subassemblies and part numbers]
Yamaha Watercraft Service Manuals PDF [lots of manuals, WaveRunner XL700 fits the bill, others as well…]
http://fos.prd.uth.gr/vas/crafts/var/Avon320-400DL2t.pdf is Vol2. Technical Specifications-Assembly procedure for the Seasport Deluxe Jet 320 & 400. That’s the steering wheel version jetski of same age. I do have my manual but it’s paper and v.hard to scan/pdf it without destroying it so not so keen. Most things are identical, service, operation, etc procedures are common, so a good read.
DISCLAIMER: anyone spent years on two stroke marine engines will find some of the following boring, apologies, I’m simply trying to show the whole process!
IGNITION:
That’s the simplest of all, replace plugs, check you have spark, do nothing if spark is good. Unless rib is flooded with tons of seawater staying in for lots of time, engine and front cover (where vital ignition bits live) will be still sealed nicely and working fine. Same applies for the black box with the actual el. Ignition unit and starter relay. However, if for some reason you need/have to remove the 250X100X60mm black box, remove the seat AND THE FUEL TANK, before you can get a socket in the two holes back there to undo the two screws holding it in place. On replacing, fit two longer M8 (iirc) hex bolts with nuts on the black box side and second washer/nut combo to keep the box in place. Next time you want to remove the box, it’s a matter of two nuts and it’s off. Not sure why they did it like that, but wasn’t smart!
FUELING:
I’d highly recommend getting 2X service kits for the MIKUNI SBN carbs. Two cylinders, two kits. A couple of links on how to dismantle and replace all vital bits on them:
Mikuni Keihin Carburetor Rebuild pt.1 [by Andrew Sands]
Mikuni Keihin Carburetor Rebuild pt.2 [by Andrew Sands]
Relatively easy job, needs a bit of care and kindness not to damage anything. Only two inner screws were a bit tough to remove, all else straight forward. If membranes/seals/whatever were never changed on yours, I’d be v. impressed if it doesn’t have some serious amounts of deposits and muck around. Don’t forget there’s no fuel pump on these two stroke motors, a pulsating membrane does the job inside the carbs, so vital to have it working fine. WARNING: check the return outlet from the second carb back to the tank. Mine was blocked after having the fuel drained for almost a year. Took a pressure hose to back flush it (part removed from carb obviously) before I could get the carbs to prime with fuel and the engine to fire!
[from Jet Ski Centre Mikuni SBN 38/44/46 Carburetor Repair Kit approx... 80euro, 3-4h job rebuilding the carbs and if you’re fast fitting them back in place J ]
These carbs have chokes and these Yamaha engines are notorious for not starting easily from cold and spending lots of time cranking. Solution is scrapping the chokes and fitting a priming kit easily sourced from jetski places. Basically replace the choke pull button on dash with a similar sized thing which is a tiny fuel pump, connected to the fuel line, remove the chokes from the top of the carbs and replace with tiny jets which pump some fuel instead straight in the carb body. Sounds simple, is simple and does wonders for cold starting! Obviously best done together with the carb rebuilt above
[Jet Ski Centre again, Mikuni Primer Kit -Options: Size: Dual, 30euro, 1h job]
Fuel tank has a 3 level sender with three 1in long areas where three individual floats (with integrated ring magnets) are moving. This matches the four dashes on the righthand side of the dash multidisplay. Mine was flashing in a random manner. Removed the sender – WARNING this means remove the whole bloody ali 40lt fuel tank which is a tight fit under the rear seat, not impossible but needs two persons to do (6screws holding it down) and undo a circlip on a circa 2in rubber cover. Now, you’ll probably find that the floaty material on the lowest or lower two floats has disintegrated due to living in fuel for the last 20yrs or so J. You can try to fix that (magnets are still there!) For example I guess you could use cork from wine bottles with a 9-10mm hole drilled in and a slot to slide the magnet in before putting it on the shaft again, or you can cut from some other material and form some floats. Note that the point where the magnet “closes circuit” so to speak is not at the top of the 1in travel but slightly (3-5mm below). FWIW, Standex Meder MS02-NBR (or PA or -PP) magnetic floats can be used. Problem is tracing them, as none seems to stock them. You want size 2 float which is approximately 25mm outside diameter, 9.1mm inside diameter and approx. 16mm height. Even if you do find them seems that minimum order is 80 or 100 pieces, good luck with the rest ?.
Due to the above, I ended up designing and fabricating new floats from a petrol resistant filament in the local 3Dprinting facility. Made them thin walled and obviously hollow to keep weight down. Works a treat although I had to go up in diameter and height to get enough volume for the thing to float, made a few extra just in case, if you want any give me a shout! BTW, make sure you put them the right way up with the magnet up.
Before embarking in a repairing job, make sure that the values with the respective magnets in the UP position, using a digital ammeter, are as follows:
Empty (all floats down): 667-713 Ohms
1/3 (bottom float up): 292-308 Ohms
2/3 (bottom and mid floats up): 97-103 Ohms
3/3 (all three floats up): 0-2 Ohms
Obviously check the fuel hoses from tank to carb in and return and replace the inline fuel filter with a new good quality one.
[s/h sender from the US for 50-60usd, or contact me for floats!]
There’s a similar setup for the oil level, haven’t touched it, bet the above apply there as well.
BODY/HULL:
There are four latches inside the superstructure once you undo them you can undo the oil filler hose (two circlips), the ON/OFF switch red cables and flip the whole thing towards the bow, giving ample space to work on the engine and paraphernalia.
Had enough to do with the other subassemblies, that tbh haven’t done anything on the hull. Didn’t need to though. Do plan to insulate the thing as it’s too noisy for my liking with some foil lined sound panels I got off the generator soundbox that I have scrapped. Exhaust box under the rear seat and fuel tank produces most of the metallic annoying 2T noise of the whole rib, easy to stuff and quieten I recon.
Regarding the tubes, it looks like the internal baffles have become detached (at least partially) so when I fill with air on one valve, the lot inflates. Not too bothered, what I’d like to know is if the tubes are pvc or hypalon, it’s quite unclear in the manual, none seems to know.
[to be continued as I hit the 10k character limit...]
seen Jeremy's williams jetrib guide and after 4 seasons of sorting out a now 20yo Avon jetrib, I decided to write down a maintenance to do (and how to) list of issues I had to address to keep a well maintained 20yo seawater jetrib in reasonable and reliable condition. Any corrections, additions, comments welcomed!
First of all, a couple of links that will help identify parts or understand how the thing works!
1999 Yamaha WAVE RUNNER XL700 (XL700X) OEM Parts, Flemington Yamaha [describes all subassemblies and part numbers]
Yamaha Watercraft Service Manuals PDF [lots of manuals, WaveRunner XL700 fits the bill, others as well…]
http://fos.prd.uth.gr/vas/crafts/var/Avon320-400DL2t.pdf is Vol2. Technical Specifications-Assembly procedure for the Seasport Deluxe Jet 320 & 400. That’s the steering wheel version jetski of same age. I do have my manual but it’s paper and v.hard to scan/pdf it without destroying it so not so keen. Most things are identical, service, operation, etc procedures are common, so a good read.
DISCLAIMER: anyone spent years on two stroke marine engines will find some of the following boring, apologies, I’m simply trying to show the whole process!
IGNITION:
That’s the simplest of all, replace plugs, check you have spark, do nothing if spark is good. Unless rib is flooded with tons of seawater staying in for lots of time, engine and front cover (where vital ignition bits live) will be still sealed nicely and working fine. Same applies for the black box with the actual el. Ignition unit and starter relay. However, if for some reason you need/have to remove the 250X100X60mm black box, remove the seat AND THE FUEL TANK, before you can get a socket in the two holes back there to undo the two screws holding it in place. On replacing, fit two longer M8 (iirc) hex bolts with nuts on the black box side and second washer/nut combo to keep the box in place. Next time you want to remove the box, it’s a matter of two nuts and it’s off. Not sure why they did it like that, but wasn’t smart!
FUELING:
I’d highly recommend getting 2X service kits for the MIKUNI SBN carbs. Two cylinders, two kits. A couple of links on how to dismantle and replace all vital bits on them:
Mikuni Keihin Carburetor Rebuild pt.1 [by Andrew Sands]
[from Jet Ski Centre Mikuni SBN 38/44/46 Carburetor Repair Kit approx... 80euro, 3-4h job rebuilding the carbs and if you’re fast fitting them back in place J ]
These carbs have chokes and these Yamaha engines are notorious for not starting easily from cold and spending lots of time cranking. Solution is scrapping the chokes and fitting a priming kit easily sourced from jetski places. Basically replace the choke pull button on dash with a similar sized thing which is a tiny fuel pump, connected to the fuel line, remove the chokes from the top of the carbs and replace with tiny jets which pump some fuel instead straight in the carb body. Sounds simple, is simple and does wonders for cold starting! Obviously best done together with the carb rebuilt above
[Jet Ski Centre again, Mikuni Primer Kit -Options: Size: Dual, 30euro, 1h job]
Fuel tank has a 3 level sender with three 1in long areas where three individual floats (with integrated ring magnets) are moving. This matches the four dashes on the righthand side of the dash multidisplay. Mine was flashing in a random manner. Removed the sender – WARNING this means remove the whole bloody ali 40lt fuel tank which is a tight fit under the rear seat, not impossible but needs two persons to do (6screws holding it down) and undo a circlip on a circa 2in rubber cover. Now, you’ll probably find that the floaty material on the lowest or lower two floats has disintegrated due to living in fuel for the last 20yrs or so J. You can try to fix that (magnets are still there!) For example I guess you could use cork from wine bottles with a 9-10mm hole drilled in and a slot to slide the magnet in before putting it on the shaft again, or you can cut from some other material and form some floats. Note that the point where the magnet “closes circuit” so to speak is not at the top of the 1in travel but slightly (3-5mm below). FWIW, Standex Meder MS02-NBR (or PA or -PP) magnetic floats can be used. Problem is tracing them, as none seems to stock them. You want size 2 float which is approximately 25mm outside diameter, 9.1mm inside diameter and approx. 16mm height. Even if you do find them seems that minimum order is 80 or 100 pieces, good luck with the rest ?.
Due to the above, I ended up designing and fabricating new floats from a petrol resistant filament in the local 3Dprinting facility. Made them thin walled and obviously hollow to keep weight down. Works a treat although I had to go up in diameter and height to get enough volume for the thing to float, made a few extra just in case, if you want any give me a shout! BTW, make sure you put them the right way up with the magnet up.
Before embarking in a repairing job, make sure that the values with the respective magnets in the UP position, using a digital ammeter, are as follows:
Empty (all floats down): 667-713 Ohms
1/3 (bottom float up): 292-308 Ohms
2/3 (bottom and mid floats up): 97-103 Ohms
3/3 (all three floats up): 0-2 Ohms
Obviously check the fuel hoses from tank to carb in and return and replace the inline fuel filter with a new good quality one.
[s/h sender from the US for 50-60usd, or contact me for floats!]
There’s a similar setup for the oil level, haven’t touched it, bet the above apply there as well.
BODY/HULL:
There are four latches inside the superstructure once you undo them you can undo the oil filler hose (two circlips), the ON/OFF switch red cables and flip the whole thing towards the bow, giving ample space to work on the engine and paraphernalia.
Had enough to do with the other subassemblies, that tbh haven’t done anything on the hull. Didn’t need to though. Do plan to insulate the thing as it’s too noisy for my liking with some foil lined sound panels I got off the generator soundbox that I have scrapped. Exhaust box under the rear seat and fuel tank produces most of the metallic annoying 2T noise of the whole rib, easy to stuff and quieten I recon.
Regarding the tubes, it looks like the internal baffles have become detached (at least partially) so when I fill with air on one valve, the lot inflates. Not too bothered, what I’d like to know is if the tubes are pvc or hypalon, it’s quite unclear in the manual, none seems to know.
[to be continued as I hit the 10k character limit...]
Last edited: