new to this jetboat thing,wife bought used challanger, previous owner had installed premium SBT engine,he said it could use wearring and impeller so..I purchased all new stock parts from dealer and with the help of this forum I installed it all with no problem. Now after warm up while running at wot the thing just shuts off,won't crank until I pull both plugs out and crank it install plugs and brought it back to shore wife wants to take it to a dealer.I thought maybe some of the members might be able to point me in the right direction so maybe Icould repair it or adjust it or something myself. all help is truly apprieciated steveb.. also no water comes out of sparkplug holes when cranking with the plugs out.yes I did put the sparkplug leads on the orange studs.have been reading,but need expert help. don't want to take it to dealer if I can fix her,summer will be over before we get her back thanks
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1996 challenger 787 engine problem?
- Thread starter steve b
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Is the engine getting fuel? If it just stopped, I would check to see if it is getting fuel. Maybe flip the gas switch to reserve to see if it gets fuel after that... Did you say it wouldn't crank till you pulled out the spark plugs? Is the grounding cable going to the engine by the starter clean and tight? I would also check that the battery wires not tight.
Keep us posted...we'll get it going again.
Karl
Keep us posted...we'll get it going again.
Karl
all battery cables clean and tight, fuel supply seems ok . seems like hydrolocked until plugs are removed. cranks ok then reinstall plugs got it running returned to shore. didnot go back out again seems to smoke alot but sbt recommends adding some oil to fuel for break in. previous owner has not return my call about questions. must be scared, I only wanted to ask him a few simple questions like did he add oil to fuel how much time on this engine and did he have similar problem before he sold it to my wife? he gave warranty papers to wife about new engine. probably something simple but need some place to start,wife sad,will be on my back soon.
If you have transferable warranty papers from SBT, you could call them and ask them what they suggest, as it is still under their warranty. I'd hate to have you do something that isn't what they would suggest as there engine warranty. Look over the warranty papers first, than either call them or re-post so we can go deeper to help get it running for you.
Karl
Karl
I thought of that also,but would not mind checking some things out first just in case it is something stupid. could it be possible that the machine is getting too much injected oil causing it to kill the engine? or possibly too much backpressure caused by excessive water in the exhaust system? do you ever have to disconnect the exhaust and dump the water out. boat doesn't look like it has been submerged. sure wish previous owner would contact me so I could ask some questions.wife feels bad now about buying the lil squirt. told her if she gave me a little time with this forum I think collectivly we can get to the bottom of this issue.she good woman but getting edgy. all help is appreciated steveb
A little too much oil from the injector or the added oil in the fuel for breakin won't hurt anything or cause it to lock up. The most it could do is foul the spark plugs. Is it possible that something is in the jet pump area, and you didn't notice it? If the ground cable isn't getting a good connection it would give the symptons of it not turning over...I have see it happen a lot that the ground isn't good going to the starter. Here are the basics to check; Good battery, good ground connection to the engine, Both connections on the battery are clean and good connections, engine has good compression(150 psi), spark plugs are the correct ones and gaped properly, engine getting fuel. I hope this info helps.
Karl
Karl
battery has been tested starter been off and looked at by local starter/alternator place,cables good.had this lock up problem before we launched the lil squirt. previous owner told wife battery could use a charge and it needed new wear ring and impeller. after taking plugs out it would crank. noticed water coming out rear exhaust while cranking. put new plugs in her and it started.then we launched her that is when it quit and we had to remove plugs to get it to turn over.reinstalled plugs got to shore and needed this forums help to get to bottom of problem,don'y give up on me yet. wife good woman would like to fix her boat.might get hugging and kissing.
I would still do a compression test to be sure what the internals are doing.
You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem.
Let me know how you make out.
Karl
You'll need a compression tester. Go to Auto Zone. I think they sell for like $25.00. The compression gage, will screw in the cylinder head in place of the spark plugs. To test compression, remove both spark plugs. Place spark plug caps on the plug cap studs near the cylinder head to ground the empty caps. This completes the circuit of the ignition electrical system and prevents any electrical problems from the caps being un grounded. Using the correct adapter for the threaded end of the tester,( same length of the spark plug threads length)screw in the tester in one plug hole. Hold the throttle wide open. Push the start button. Watch the compression gauge, when it peaks out at the most compression, let go the start button. Read the psi number. I would do it 3 times to be sure it is accurate. Check both cylinders the same way. The ideal compression is 150 psi per cylinder. If it is less, it's not a problem as long as they are close to being the same. If the psi is less than 90 it might need be time for a tear down and a rebuild. If the psi in 1 cylinder is say 140 psi and the other is 80 psi you need to tear down and repair. This difference is a lot and there is a problem.
Let me know how you make out.
Karl
karl, does sbt sell many engines thatwould require this so soon I know what you are saying do the test just to be sure.if it is low or uneven I guess the sbt warranty would need to be used.but when the lil thing was running it went like a scared cat then just shut off.I'll do test tomarrow will keep you posted. if you can think of any other things to test or check wife would be very happy to know Im working toward a resolution. thanks steveb
Its hard to help diagnose a problem over the computer...The only thing I can really suggest is to do some basic things to cover all the bases. It might have great compression but until its checked, we are only guessing it is good. We could check all kinds of things and still have the same problem. Then if we did check the compression and it was low we wasted a lot of time and energy. We need to cover the basics, than we can solve the problem.
Be sure these are the spark plugs used and the gap also.
Spark Plugs for 2 stroke NGK BR8ES Gap/ 0.5-0.6mm or .020-.024in.
I see your from Up State N.Y. I'm from the Albany / Columbia County area myself...
You need to add your model and year in your avatar so it is always at sight as we try to figure out your next step.
Karl
Be sure these are the spark plugs used and the gap also.
Spark Plugs for 2 stroke NGK BR8ES Gap/ 0.5-0.6mm or .020-.024in.
I see your from Up State N.Y. I'm from the Albany / Columbia County area myself...
You need to add your model and year in your avatar so it is always at sight as we try to figure out your next step.
Karl
That is close...I moved here with my family back in 1996. Now I get to boat all year long. :hurray:
let me know how you make out.
Karl
let me know how you make out.
Karl
karl, I tested compression today on 1996 challenger single 787 and got 145 bow 140 stern cylinder. sitting on trailer today I tried to start it and it turned over with no problem? just a little hesitant to launch it and have same problem wifes heart would be crushed. going to lave a lok at carbs tomarrow steveb
timmyboy76
New Member
hey steve....my .02, since your pull'n the carbs, take a gander at the raves, also if isnt too bad, with carbs off, pull intake off ,and recheck the RV timing...147*opening...
It sounds like your in pretty good shape Steve. Give us a shout if you get in a bind.
Karl
Karl
karl, decided to go the carb route check clean etc.. then launch the lil squirt and try this jet boat thing again hopefully every thing will be ok not taking wife to lake don't want her to be disappointed in case we have more issues. cross your fingers and maybe the next post will be about my jet boat experiance on cossayuna lake.
Good luck with it Steve. Keep us posted.
Karl
Karl
karl, removed carbs and had a friend of mine that works at a motorcycle shop open them up and inspect them. said everything looks fine. I invited him to ride out on the lake. after warm-up ran about 10 minutes stalled had to remove plugs to get cranking again,this only happened once. the rest of the ride we had it stop a few times but didnot have to remove the plugs. going to get a better look at the fuel supply, hoses shut off valve reserve hosing. wife feels better about bout thinks we are making progress,I hope she's right.still dont understand the no crank until plugs are removed but it bothers me some. plugs had light brown color looked ok to me. steveb
That is strange Steve. Let me know if it does this weekend if you get out on the water. The spark plugs sound like there ok too. Be sure the gap is correct, and the right plugs.
Spark Plugs NGK BR8ES Gap/ 0.5-0.6mm or .020-.024in.
Karl
Spark Plugs NGK BR8ES Gap/ 0.5-0.6mm or .020-.024in.
Karl
karl, ran on water today for about 20 minutes shut down a couple of times but was against the rev limiter. think I might have a handle on the engine. but ,the lil sob would not come up and plane out. checked the intake grate could not find any apparant problems, impeller and wear ring are brand new stock seadoo parts? my question is the lake is very weedy floating 6 inches under surface.could this be impeding proper water flow into the impeller area. have you heard of this before. going to a deeper part of the lake tomarrow to test my guess,I'll keep you posted. If you have any ideas please post. thanks steve
Steve, I have encountered weeds in the ICW here in Florida too. I haven't ever had a problem cause it doesn't suck them into the Jet pump. I stay away from those areas at low tide. Be sure you getting full throttle on you carbs. Check it when it's NOT running. Here is some information I used on my 1997 Challenger to get maximum Throttle, and Forward Thrust from it. After my adjustment I gained like 8 mph from when I bought the boat, and it was adjusted by a seadoo dealer by the previous owner.
Shifter adjustment on a jet boat;
Fully pull the throttle lever to the idle position then pull the shifter in reverse position. Ensure reverse gate ear contacts the stopper, on the nozzle assembly. Check on both sides for it to touch the nozzle. Next fully push shifter in forward position. A latching sound should be heard. Try manually pulling reverse gate down. They must be locked by the latching mechanism. If either check fails readjust the cable to meet both conditions.
Throttle cables adjustment;
Fully push throttle levers. Be sure there is no strain in the cable or carburetor cable bracket. Make sure carburetor butterflies are fully open at full throttle position. At this position, throttle stop lever will almost contact carburetor body.(0.4mm or 1/64in.). Improper cable adjustment will cause strain on cable and/ or damage cable support or throttle lever at carburetor. To adjust, loosen jam nut; turn adjustment nit as necessary. Tighten the jam nut and recheck adjustment. If more adjustment is required than carburetor cable adjustment can provide, adjust cable at throttle/ shifter control. Be sure the cable housing end does not touch the throttle lever cam when moving it.
Unscrew throttle / shifter control from boat. Adjust the adjustments under the throttle controls. Replace when finished. Be sure idle speed screw contacts stopper when throttle lever is fully pulled back at throttle lever control.
After throttle cable adjustment, always proceed with oil injector pump adjustment. Be sure the marks on the pump line up and both the oil pump and carbs are in sync.
After adjustment verify all adjustment are working properly before running engine.
This will make a huge difference if adjusted correctly.
Karl
Shifter adjustment on a jet boat;
Fully pull the throttle lever to the idle position then pull the shifter in reverse position. Ensure reverse gate ear contacts the stopper, on the nozzle assembly. Check on both sides for it to touch the nozzle. Next fully push shifter in forward position. A latching sound should be heard. Try manually pulling reverse gate down. They must be locked by the latching mechanism. If either check fails readjust the cable to meet both conditions.
Throttle cables adjustment;
Fully push throttle levers. Be sure there is no strain in the cable or carburetor cable bracket. Make sure carburetor butterflies are fully open at full throttle position. At this position, throttle stop lever will almost contact carburetor body.(0.4mm or 1/64in.). Improper cable adjustment will cause strain on cable and/ or damage cable support or throttle lever at carburetor. To adjust, loosen jam nut; turn adjustment nit as necessary. Tighten the jam nut and recheck adjustment. If more adjustment is required than carburetor cable adjustment can provide, adjust cable at throttle/ shifter control. Be sure the cable housing end does not touch the throttle lever cam when moving it.
Unscrew throttle / shifter control from boat. Adjust the adjustments under the throttle controls. Replace when finished. Be sure idle speed screw contacts stopper when throttle lever is fully pulled back at throttle lever control.
After throttle cable adjustment, always proceed with oil injector pump adjustment. Be sure the marks on the pump line up and both the oil pump and carbs are in sync.
After adjustment verify all adjustment are working properly before running engine.
This will make a huge difference if adjusted correctly.
Karl
karl, ran the lil sob on deeper part of lake no difference. when you finally get her to plane out got about 45 mph. don't think speedo is that true but didnot gps the thing. ran for about 20 min. stalled got towed to the launch and loaded the thing .brought back to my camp and totally disassembled the fuel system ie. lines selector valve no gunk could not see any thing. what are these 2 check valves people have talked about? was a lot of fun for about 20 minutes though. steveb
You have the 787 engine with RAVE valve. Has the RAVE been cleaned? here is some information on the RAVE;
The RAVE, (Rotax Adjustable Variable Exhaust) valves are located above the exhaust valve. There are 2 of them per engine. They are round with a red adjustment screw in the middle. It has a clip that holds it together. How they work is that they open the exhaust port larger as the engine rpm's increase. When the rpm's drop down so do the RAVE valves. They work on the principle of the pressure of the exhaust system. Rpm's increase, pressure increases and the valve opens, rpm's drop pressure drops, Valve closes. They should be de-carbonized annual. To disassemble the rave valves, remove the spring clip on top, remove the black cover. There is a spring under the cover. Remove the piston by turning it with a metric socket. On the bottom of the piston is the rubber "Bellows" be careful with the small retaining spring that hold the bellows on the piston. Remove the 2 allen screws that hold the base on the cylinder. Remove the base and gasket. The long valve won't fall in the cylinder just pull it out. There is an o ring under the base, on the shaft of the guillotine valve. Be careful to see how it came apart as it has to go back together that same way again. On the base, notice the notch that it is facing down. Clean all the carbon off the guillotine valve. I use carb cleaner and 400 grit paper. Check the bellows for any small pin holes. If so replace it. If not, reassemble it on the clean guillotine valve, and install it back on the engine the same way it came apart. The guillotine valve only fits one way. The one closest to the exhaust pipe will come off differently then the other one. You will have to remove the allen screws and turn the base so it clears the exhaust pipe. I would do one at a time in case you forget how it goes back together again. This way you can look at the other one and copy it. Take your time and if you have questions give us a shout. We'll be here to help you out.
If the RAVE valves are dirty it will not rev up correctly and could be causing your problem.
The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performance, as far as how it jumps out of the hole or how well it runs for extended periods at WOT.
Karl
The RAVE, (Rotax Adjustable Variable Exhaust) valves are located above the exhaust valve. There are 2 of them per engine. They are round with a red adjustment screw in the middle. It has a clip that holds it together. How they work is that they open the exhaust port larger as the engine rpm's increase. When the rpm's drop down so do the RAVE valves. They work on the principle of the pressure of the exhaust system. Rpm's increase, pressure increases and the valve opens, rpm's drop pressure drops, Valve closes. They should be de-carbonized annual. To disassemble the rave valves, remove the spring clip on top, remove the black cover. There is a spring under the cover. Remove the piston by turning it with a metric socket. On the bottom of the piston is the rubber "Bellows" be careful with the small retaining spring that hold the bellows on the piston. Remove the 2 allen screws that hold the base on the cylinder. Remove the base and gasket. The long valve won't fall in the cylinder just pull it out. There is an o ring under the base, on the shaft of the guillotine valve. Be careful to see how it came apart as it has to go back together that same way again. On the base, notice the notch that it is facing down. Clean all the carbon off the guillotine valve. I use carb cleaner and 400 grit paper. Check the bellows for any small pin holes. If so replace it. If not, reassemble it on the clean guillotine valve, and install it back on the engine the same way it came apart. The guillotine valve only fits one way. The one closest to the exhaust pipe will come off differently then the other one. You will have to remove the allen screws and turn the base so it clears the exhaust pipe. I would do one at a time in case you forget how it goes back together again. This way you can look at the other one and copy it. Take your time and if you have questions give us a shout. We'll be here to help you out.
If the RAVE valves are dirty it will not rev up correctly and could be causing your problem.
The adjustment knob (the red cap) should either be screwed all the way in or flush to the top of the black ring of the cap. This will only affect performance, as far as how it jumps out of the hole or how well it runs for extended periods at WOT.
Karl
karl, thanks for the info about the rave valves,we will look at them today. the check valves that I was refering to I think I read someplace or in the fuel lines? maybe I misread the link? might no be so good fixing jetboats but I can really make a freightliner go.thanks steve
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