bayliner Jaz 1994? no propulsion

[laurencen]

hello all, got a Bayliner Jaz I believe to be 1994 vintage, going to try to fix it but the previous owner says it runs fine and it appears the motor is running good however he says when in the water the behavour is as if tied to the dock, will only reach maybe 5mph, says lots of water displacement but no movement.

from what I know he replaced the starter, impepper and wear ring, seals, replaced the water inlet screen but nothing seemed to work so I ended up with it. He has bills for a couple grand in parts not all for the jet

the guy has spent a lot of money to get nothing worth his effort, I have ran the motor and it seems prety good other than needing a bit of gas in the carbs to initially start it, revs up fine but its a couple hours to a body of water and was hoping someone has a idea what to look for before I take it out

this boat has some negitive reviews but for me its a play thing to explore our rivers

thnaks in advance

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

one other thing, there is a neutral button on the forward / reverse lever, from what I understand it is used to rev the engine without turning the impellar, I thaught a jet drive was allways direct, does this jet drive have neutral and disengage the impeller somehow, if so where does this take place or is there a clutch possibly spring opperated, maybe this is not engaging the impellar, this would maybe explain the previous owners comment lots of water but acts like tied to the dock

thanks

 

[jackd1023]

Re: bayliner Jaz 1994? no propulsion

I would pull the jet pump and check the wear ring and the impeller, chances are something is broke,

 

[oldjeep]

Re: bayliner Jaz 1994? no propulsion

Have you checked that the reverse gate is actually opening all the way when in forward?

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

impeller and wear ring are new, gate is working correct, the previous owner did have the intake plate straightened, doing some reading and the exhaust seal is required, anyone know if the seal is poor can this cause my issue? can not find anything broken

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

impeller and wear ring are new, gate is working correct, the previous owner did have the intake plate straightened, doing some reading and the exhaust seal is required, anyone know if the seal is poor can this cause my issue? can not find anything broken

 

[jackd1023]

Re: bayliner Jaz 1994? no propulsion

I would think then it is the coupler, Not for sure which one they used on those, Fairy easy to check with a wrench

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

the coupler is good, the intake plate sits below the hull by 3/4 inch, he had this straightened maybe leaking

 

[einnuyuk]

Re: bayliner Jaz 1994? no propulsion

the coupler is good, the intake plate sits below the hull by 3/4 inch, he had this straightened maybe leaking[/QUOTE

The intake plate sits that low because he used it as a trim for it to plane faster and prevent porpoising. I order trim tabs rather than making that modification. The only thing I can tell you is to see if he has the standard impeller on there, that's if the 3/4" hang isn't a trim mod, but an impeller modification.

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

here is a update, took the intake and larger plate off, the impeller is definatly newer and wear ring looks good, there is only thousandths clearance, it now seems the exhaust gas could be entering the water intake but here is the question, the intake and plate were sealed with silicone, it looks like exhaust enters the cavity between the motor and this plate then goes thro this cavity to 2 openings each side the jet and exits the end of the jet, the ride plate was sealed for the most part but not at the side foam strips left and right of the transom, also the end of the ride plate and intake screen, could this area allow enough exhaust gas to cavitate the jet pump, hence 10mph from just above idle to cruise rpm? I could see if the pump is sucking air and water the thrust would be greatly decreased, ideas??

 

[tech 3]

Re: bayliner Jaz 1994? no propulsion

here is a update, took the intake and larger plate off, the impeller is definatly newer and wear ring looks good, there is only thousandths clearance, it now seems the exhaust gas could be entering the water intake but here is the question, the intake and plate were sealed with silicone, it looks like exhaust enters the cavity between the motor and this plate then goes thro this cavity to 2 openings each side the jet and exits the end of the jet, the ride plate was sealed for the most part but not at the side foam strips left and right of the transom, also the end of the ride plate and intake screen, could this area allow enough exhaust gas to cavitate the jet pump, hence 10mph from just above idle to cruise rpm? I could see if the pump is sucking air and water the thrust would be greatly decreased, ideas??

I have been folowing your thread maybe we can put our heads teoughter and figure this out
my question is do you know how many RPm's you are turning when your at WOT out of the hole
Bill (tech 3)

 

[einnuyuk]

Re: bayliner Jaz 1994? no propulsion

You mentioned everything under the boat is fine so how about trying to clean the carbs. If you rebuild them or remove them make sure you lync and sync correctly. Many boats run like a beast out of water, but when put in the water under load it would bog down after giving some throttle, even got to the point where weight would affect bogging (i.e. passenger in the bow). Turned out, they didnt have the carbs lynced and synced correctly.

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

not measured the rpm but it idles fine, revs up lower mid range and moves maybe 10mph, when wide open its screaming the jet does not get any better for thrust, lots of turbulance under the back of boat, gate is good just no power, like tied to dock, now looking at the exhaust gasses entering the intake, ever heard of this?

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

should also add, the drive plate was sealed well sides and front, no way to seal at the rear where thr inlet screen goes, there was also some leakage obvious front right corner where the rubber gasket contacts the boat underside, the area I am looking at there is 2 foam gaskets more blocks about a inch thick, these are vertical and where they should contact the drive plate there is obviously a small gap, I assume this cavity is where exhaust gasses enter then thro a tunnel to the bacl of the jet output, never looked at this when we tried it inwater but if this is idling 1500rpm the jet looks good but higher it gets air in the stream, at high rpm this exhause I think escape and get sucked up in the inlet and cavitate the pump, does this sound like Im on the right track, in spring I will do a carb job around here now we have a foot of ice on the lakes so other than taking apart and looking its dry docked

 

[sixfigures]

Re: bayliner Jaz 1994? no propulsion

Jets are very particular about cavitation, the exhaust entering the pump may slow the top end down by mixing air in the jet force exiting the nozzle, the angle of the intake grate is also importand as is the correct pitch of the impeller and the correct clearance of the pump liner to the edges of the impeller.
Those boats used a force outboard powerhead with a pump body that had a splined shaft coming out of the pump and entering the crank shaft similar to a lower unit on a normal outboard.
This was an adapation of the outboard engine and a pump .
There are splines that could be slipping between the pump shaft and the crank or a set of gears similar to the lowerunit of an outboard only direct drive with no shift dog as there is no real neutral or reverse. The reverse gate redirects the water exiting the nozzle.
Basically you will need to confirm that the splines are good and not slipping and the gears are good where it changes from vertical to horizontal inside the pump.
What makes me suspicious is the mention of intake being straightened by the previous owner ., damage to the intake is usually caused by the pump ingesting a rope or some other item that could have locked up the pump at speed and stripped a piece in the drive line.
It may have no internal isues at all but you have apparently ruled out the normal causes like a bad pump liner or impeller and as for the ride plate being angled for plaining I would try putting that back to it's correct position just to rule that out also. Any obstruction of the water flowing to the pump can cause cavitation. This would mean the engine is hitting the R P M's but the pump is not producing the correct thrust. And as previously mentioned you can not test anything on the trailer so you won't know until next spring when you test it in the water.

 

[tech 3]

Re: bayliner Jaz 1994? no propulsion

should also add, the drive plate was sealed well sides and front, no way to seal at the rear where thr inlet screen goes, there was also some leakage obvious front right corner where the rubber gasket contacts the boat underside, the area I am looking at there is 2 foam gaskets more blocks about a inch thick, these are vertical and where they should contact the drive plate there is obviously a small gap, I assume this cavity is where exhaust gasses enter then thro a tunnel to the bacl of the jet output, never looked at this when we tried it inwater but if this is idling 1500rpm the jet looks good but higher it gets air in the stream, at high rpm this exhause I think escape and get sucked up in the inlet and cavitate the pump, does this sound like Im on the right track, in spring I will do a carb job around here now we have a foot of ice on the lakes so other than taking apart and looking its dry docked

Greetings
I was thinking about your problem and I dont think that exhaust gasses are the issue
I would look at the timming and the carbs
my Searayder is heavyer than your Jazz and it takes 4800 rpm's to get it on step
when I first got it I had problems getting it up on step I did not have a tach at that time
since then I removed the speedo and installed a tach,I had to go through the carbs to get it to make full
power when you go through the carbs make sure to pull out all the little plugs and run a guitar string
through the little holes and blow out with compressed air mine would not make full power until I did this
now it runs great Hang in there it is a great little boat I can run around about 5 hours and still have just a little
less than 3/4 of a tank of fuel left over
Keep us updated on your progress If I can help in any way let me know. Bill (tech3)

 

[einnuyuk]

Re: bayliner Jaz 1994? no propulsion

Greetings
I was thinking about your problem and I dont think that exhaust gasses are the issue
I would look at the timming and the carbs
my Searayder is heavyer than your Jazz and it takes 4800 rpm's to get it on step
when I first got it I had problems getting it up on step I did not have a tach at that time
since then I removed the speedo and installed a tach,I had to go through the carbs to get it to make full
power when you go through the carbs make sure to pull out all the little plugs and run a guitar string
through the little holes and blow out with compressed air mine would not make full power until I did this
now it runs great Hang in there it is a great little boat I can run around about 5 hours and still have just a little
less than 3/4 of a tank of fuel left over
Keep us updated on your progress If I can help in any way let me know. Bill (tech3)

Total agreeance Tech3. He really should look into the carbs before breaking the "Jazz" down any more than what's been done. One great thing, out of Laurencen's dedicated work, is he will know his boat from bow to stern.

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

well put the seals in hull and mounted the ride plat, sealed it up as good as I can, the inlet screen after looking at it appears like something fabricated, I would have expected something better made, I have to check another boat and see but at least its back together, will start the carb cleaning tonight, I know its hard starting when cold, the last owner had to give it a shot of gas in the carbs to get it going so now is a good time to check this out, I think remove the plugs, hang then to protect the ignition module and crank it over a few times then see if gas is actually getting to the carbs and further yet into the cylinders, I did notice the plugs after lots of cranking are not wet, thanks for the help

 

[einnuyuk]

Re: bayliner Jaz 1994? no propulsion

Mine is in the garage, what type of pictures do you need?

 

[laurencen]

Re: bayliner Jaz 1994? no propulsion

if you can take a picture of the suction screen, also the ride plate, one of the ride plate looking from the jet would show this seal I had issues with, thanks