115 OMC cutting out at high RPM -- bulb loses preasure

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rmeyer333

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Jul 30, 2004
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At the end of last year, I was unable to start my 1995 115HP TurboJet. I installed a primer bulb on the gas supply and the engine would start. But now the engine will "hesitate" at mainly higher RPM's. The engine will slow down and then kick in again and on and on. Everyonce in a while it will keep going for 2-3 minutes without hesitation.<br /><br />I also installed a new VRO unit to see if that was the problem with no luck.<br /><br />The primer bulb loses "hardness" during the higher RPM's -- after I pump up the bulb, then the engine seems to run ok for a few minutes.<br /><br />Any ideas?<br /><br />Thanks for your help.
 
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Hooty

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Re: 115 OMC cutting out at high RPM -- bulb loses preasure

The only time the bulb should be hard iz when you pump it. After the engine starts and there's fuel flowing through it, it will lose it's hard.<br />However, if pumping the bulb helps the hesitation, it would appear that the problem is fuel related. Carefully inspect the fuel line from the tank to the bulb and make sure all fittings are secure and there no leaks that would allow air to be sucked into the system.<br /><br />c/6<br />Hooty
 
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rmeyer333

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Re: 115 OMC cutting out at high RPM -- bulb loses preasure

Thanks Hooty -- that helps understanding the "bulb" part of the equation. <br /><br />So your thoughts would be that air is being sucked into the system? At idle the engine does not hesitate, only at higher rpm's. <br /><br />So if I understand correctly, the fuel system needs to be "sealed" in order for the engine to "pull" the fuel from the gas tank? That would explain why it would not start and then I added a bulb (which it never had for the other 9 years) and it started right up.<br /><br />Any other places I should be checking for air leaks?<br /><br />Thanks again for your help.
 
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Hooty

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Re: 115 OMC cutting out at high RPM -- bulb loses preasure

You understand correctly. The fuel pump pulls the fuel from the tank to the engine. If there's any leaks, the pump will pull air instead of fuel because air's so much nicer.<br />That's just one possibility though. The problem could be with the fuel pump or maybe even a carburetor. It may not even be fuel related but the fact that pumping the bulb seems to alleviate problem points that way. Keep us posted.<br /><br />c/6<br />Hooty
 
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mtemple

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Jun 16, 2002
Messages
25
Re: 115 OMC cutting out at high RPM -- bulb loses preasure

I had this happen once and it was a fuel filter that was at the tank. The motor would run fine at an idle and just quit at high speeds. The bulb would almost go flat at high speeds. Finally found the filter at the tank (not an easy job on that boat) replaced it and things were fine.
 
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rmeyer333

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Re: 115 OMC cutting out at high RPM -- bulb loses preasure

Thanks for the replies -- I'll give them a try.
 
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