93' Tigershark power loss problems

[tjgrams]

I have a 1993 Tigershark 640 that is having power loss problems, it will start up and idle fine and will achieve full power for about 25 seconds and then it will lose power and start "stuttering", if I shut it off and immediately start it up again it will again run at full power for about 25 seconds and then begin stuttering again and have no power. It does this in the water or on the trailer.

It doesn't seem to be a fuel problem, checked the carb and the fuel delivery lines and even tried giving it a little fuel through the carb when the power loss started to happen, but didn't make any difference. Any suggestions on what I should check/test?

[Randy R.]

Re: 93' Tigershark power loss problems

Heat sensor maybe? Im sure others know more than me, but i was thinking that maybe the heat sensor is kicking in and killing one of the cylinders. Since a 640 is probably running only one carb, i was doubting that one cylinder is loading up on you. are you sure its not something in the fuel line? maybe a fuel filter, water in the tank.... I noticed on mine that the return was not returning anymore at half throttle, which was caused by a clogged fuel filter. Just a few thoughts...

[tjgrams]

Re: 93' Tigershark power loss problems

I did think it might be the heat sensor, since its acting like one of the cylinders is cutting out after about 25 seconds, after work I'm going to see if I can check the sensor more in depth, I checked to see that coolant was flowing past it in the exhaust elbow and tried running it with the sensor in open air instead of screwed in place and that didn't seem to make any difference, unless possibly there is a delay in the system and the sensor is bad...

[molad]

Re: 93' Tigershark power loss problems

my 95 is doing about the same thing. It runs for a few seconds and then just dies like it has no fuel. I was guessing it is something in the carb, but hadn't checked yet. After reading replies to others I am sure that is the problem. Thanks

[tjgrams]

Re: 93' Tigershark power loss problems

I'm disinclined to believe that it is the carb on mine as I disassembled it and checked it out and it seems to be in excellent condition, and giving it a bit of fuel when the powerloss happens has no effect. If anyone has any suggestions on what I might test on this....

[tjgrams]

Re: 93' Tigershark power loss problems

Ok, so I found that the temp sensor switch is bad and I disconnected it to test out the motor without the sensor, and it will run a bit longer at full throttle before starting to stutter and act like its only running on 1 cylinder but it still does it, anyone have any ideas on what I should try?