Please help to diagnose the engine problems with LS2000

[malashev11]

I bough a 1999 ls2000. The engines seem to start right up (with started fluid) and the first 2 times on water it worked great. got up to speed and throttles just fine. At the end of the second day right engine started to just shut off randomly but start right up again. this problem got worse very quickly and by the time i got to the dock i couldnt keep it running at all. Same thing is happening to the right engine right now, it starts and runs but then shuts off randomly and i have to baby throttle to get it above 3k RPMS. so back to the dead one, I got home and rebuild the carburetor. Installed the rebuilt carb and started in the driveway, no problems. It reved above 4k rpms for a few seconds and kept idle just perfect. I though everything was good so took it out to a lake again and same thing happened, the second it was in the water it would start just fine but would not rev up and would die at idle few minutes later. I took it out of the water and went to play with some other toys for 5+ hours. Then i attempted to start it while it was on the trailer and it would be same thing, real difficulty idling and would not rev. after a few seconds idle stabilized and it was reving again just fine on the trailer and i saw a fairly big puddle of water under that jet. So i'm sort of thinking it has trouble under load now but i dont even know where to start figuring out whats the cause. I am not a mechanic, i'm good with a wrench but i can not diagnose problems without google and there isnt many write ups for these boats so i am here hoping someone knows what it might be.

both shake pretty hard while idling, about equally hard but when reved they seem very smooth, almost no vibration so i think that might be normal.

When i was taking off the carb i made sure it had fresh oil out of the drip holes for the oil injection system, so i know that part works, i also made sure it was bled through and no clogged lines. I replaced fuel filters just cause its a cheap part and gave me a piece of mind and spark plugs since they had some unburned gas on them (which is what made me think it was the carb). i assume fuel pump is good since it will rev and well above 4k rpms out fo the water and very responsive to the throttle out of the water since the carb has been rebuild. BTW, i adjusted high speed and low speed settings on the carb by the owners manual specs.

I'm thinking to take it to a mechanic to have them diagnose it but i dont have that many near by and none i would trust here since closest lake is 4 hours away and they wont even be able to test the problem without going there.

Any thoughts would be appreciated.

 

[bronze_10]

Bad fuel maybe.... it would be odd that both engine have different issues at the same time....

 

[DCB-270]

Did you do a compression test?

 

[Bruce]

Seafoam fixed an occasional stalling problem with the engines in my LX210. It sounds like you have taken care of the carbs but it might help with something elsewhere in the fuel system.

Have you changed the fuel filters recently?

 

[malashev11]

yes, new filters on the hose and in the carbs. i havent done compression test yet. i dont have the gauge and borrowing it from a buddy this weekend.
fuel is good for sure. when i got it it had very little in there and i filled the tank myself and it ran great for 4 hours or so combined.

thats the thing, 2nd engine is acting the same way as first one did at first, it just seems left engine progressed so much faster/worse.

 

[bronze_10]

If it sat for a long period with little fuel in it water could have accumulated. .. or there is no guarantee the fuel is good from a gas station... I have seen on here people talking about additives that can help remove water from the fuel.. seafoam maybe.. I'm not sure.

 

[malashev11]

i'll try that just to eliminate it as one of the possibilities but i really dont think thats it.

i put same fuel into my car right after i filled the boat and it ran well at first. right engine is also gets into higher rev's while on the water while left only does on the trailer.

 

[bronze_10]

When I worked on commercial motor vehicles and needed to check the tank for water I found a long tube, ran it down into the tank and held my thumb over one end... pulled it out and let what was caught in the tube out into a bucket... if there is water in it .. it was easy to see.. will tell ya if u your tank has water in it.. water can get in a car or truck tank in many diff ways.. I'm sure a boat is just as easy

 

[Yamatuf]

Sounds like water in gas or maybe plug wires/caps bad. I had bad plug wires. jetskisolutions hooked me up with new wires.
A cylinder down due to bad wires will cause the vibration from misfire.

 

[4x15mph]

I would be careful about using starter fluid since it doesn't have the lubrication that the 2 stroke needs. I am having trouble following the sequence of events with the 2 engines and then I see that you do not have a lot of experience but you rebuilt the carbs??? PM me if you want to call and talk about this further. Welcome to the site and you will love the boat once you get through the learning experience of maintaining it.

 

[Gmmastertech1]

Definitely do a compression check. You're guessing at things without knowing the compression. Do NOT use starting fluid. You'll dry the cylinders quickly and possibly do damage. You said you rebuilt the "carb". Are you referring to one or did you rebuild all three? Did you use factory Mikuni kits? Aftermarket are worthless. First things first, you need to know the mechanicals of the engine are where we want them and then move to the electrical side.

 

[malashev11]

Thanks for all the replys and ideas. unfortunately its the engine. 60 psi on all 3 cylinders and both engines. guess i'm getting some new engines.
anyone know of a how to convert to pre mixed gas set up? or mixing guides. i never had a two stroke so i have no idea what i am doing with it.
to go to premixed set up do i just get rid of the lines feeding the oil or should i remove the whole assembly they run through?

 

[Cobra Jet Steering LLC]

Sounds like the compression gauge to me, 60 on every cylinder is nearly impossible odds. spray oil in the cylinders crank the engine and be sure to open the throttles to let air in, also be sure to have the gauge in properly. I believe you have a fuel issue probably dirt in the tank clogging up things. or a bad ground wire from the battery to the engines. any compression below 80 the engines won't run, what color are the plugs? lt. brown is perfect, black is rich, grey or silver means water in the fuel or in the combustion chamber " usually the kiss of death as is a bent electrode. Air blowing out the carbs is bad reed valves, just things to look at.

 

[Julian]

What @Cobra Jet Steering LLC said....just cuz you bought good gas doesn't mean you don't have water sitting in the bottom of your tank (or dirt). At home, not moving, runs fine, drive it to the lake, shake it up, and now you've mixed in the contaminant, and runs rough or dies. Same for bad connection...though less easy to explain....running over waves causes wire to shift....I actually had this on my cycle LX210 though (wire at the starter was loose)....but only on one engine....so unless its at the battery, hard to explain why both are acting up. Sea Foam would be my first approach...

 

[Cobra Jet Steering LLC]

I know of someone who had some dirt in the tank that looked like fine silt as the fuel pump pulled it to the screen on the pickup in the tank it would collect to the point of shutting off the fuel supply. After the boat sat with the engine off the trash fell back to the bottom and the cycle started all over again. if you did not actually look in the tank you don't know if there is dirt sand who knows what in the fuel tank or someone was adding 2 stroke oil to their fuel and it coagulated in the bottom of the tank. I would definitely go back to the compression gauge and get a good reading before you teat down the engines .

 

[malashev11]

yeah. throttle was open all the way. anyone know how to do a proper leak down test on 2 cycles? i'm not 100% positive when 2 cycle intake pressurizes the mixture vs evacuates the gasses. i think a leak down would be best to figure out if its the rings or valves.
I can try again. get a different pressure gauge and test again. It was deff screwed in all the way.
so one thing i left out was the first day i got the boat my step dad took it out and ran it for the first 3-6 hours until i got to the lake. the pee holes were clogged at the top. but looking at diagrams it doesnt mean it wasnt working 100%, just means circulation wasnt great because the clogs were at the exit point, just sand blew in there.


I still dont think its the sand in the gas tank because one engine runs. not great and i have to baby the throttle but it runs.
i've replaced fuel filters both in the carbs and on the lines.

one thing i did notice last time i was messing with it is that the dead engine doesnt really smoke, i mean some at high rpms while the right one smokes like a proper 2 stroke. which could also point towards clogged fuel lines, or pressure leaks. i think what i really need is a proper leak down test to figure out if it looses pressure or not.

i'm thinking to swap out the fuel lines and try it in the water. if right engine behaves like the left one has prior to swap than its the fuel. Sux i got to spend another weekend and 80$ towing it to the lake next sunday.

 

[Cobra Jet Steering LLC]

It's a 2 stroke engine there are no VALVES, just get a good compression test on it . smoking could be anything but bad rings because there is no oil ring again it's a 2 stroke engine. I can tell you how to check the end play on the connecting rods but for now you need a good compression test done.

 

[malashev11]

I mean the lack of smoke might point towards leaking cylinder since not enough fuel get ignited due to leaks.
thanks, i will get a new gauge from autozone and test it again when wife gets home from work.

 

[Cobra Jet Steering LLC]

really, start with that, all your cylinders can not be 60 , when they act up like this it us either fuel system or electrical even the rear hatch switches can make the engines stall . one or the other or both.

 

[malashev11]

when i replaced the plugs they were black and wet, gas oil mixture. thats what prompted me to rebuild the carbs.
I got seafoam in the tank now. I'll do a pressure test tonight and let you guys know the outcome. I though 60 on each was odd too, it was with in 5 psi difference so i just called it 60. but within 5psi is still too uniform.