LOSING POWER

[j_m_henderson]

• <br />115hp OMC V4 losing rpms. Changed plugs, fuel filter, and carbs have been cleaned?<br /><br />Is there a Vent or Vac. line I need to check????<br /><br />Help!<br />

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[JB]

Re: LOSING POWER

What year is your 115, John? Do you have a tachometer? We need a more detailed description of your problem; running conditions, rpm if possible, etc.<br /><br />Standing by. . .<br />JB

 

[j_m_henderson]

Re: LOSING POWER

It is a 1994 i/o -OMC-Turbo Jet. No, unfourtunetly I don't have a tach. From what I can tell the motor runs about 4500-5500 r's @full throttle. I have had the boat for about a month! <br />What happened when it broke--> The boat started a little hard that morning, but ran @full open across the lake a couple of times. I idled in the middle for about 3-5min then she wouldn't come up to full rpms. Went to shore and changed the fuel filter after scratching my head with no luck. Then when I took it to put it on the trailer she ran @full most of the way back to the dock but lost power before trailering!<br /><br />I am new to boats but not wrenches, just not sure what to look for!<br /><br />Thanks

 

[JB]

Re: LOSING POWER

Sorry, John. I am unfamiliar with your application. Power loss is usually due to loss of a cylinder or fuel starvation. Yours seems to be temperature related and may be a function of an OMC S.L.O.W. system reducing the power to save the engine.<br /><br />Hope that helps.<br />Red sky at night. . .<br />JB

 

[Zebramidge]

Re: LOSING POWER

i have the same motor on a boston whaler jet boat recently purchased. have done similar maintenance but have yet to exceed 4750 rpm at wot even though i believe the boat should give more. cleaning up some small fuel leaks, replacing leaky vro pump and decarbonizing carbs added about 250 rpm. did compression test and got 140/135 starboard and 125/125 on port pistons. this 2 stroke is very smokey at startup. considering trying sythetic oil. what was your initial experience on rpm output? have you done comp test? have you experimented with different octane fuels?

 

[rlouns]

Re: LOSING POWER

I am no expert but I just went through a similar problem (see 1991 90 HP force). It ran good then went to half RPM's then ran good and then went to half RPM's. Good compression. Finally stayed at half speed at WOT. I found a broken wire to my #2 coil no spark for the number 2 cyl. The wire was not seen until it vibrated out of the rubber sleeve that was covering the crimped portion of the connector.<br /><br />Worth a look (tug on all of the wires). If they are touching occassionally it will give this problem.<br /><br />Lots of Luck.<br /><br />Robert

 

[bkearse]

Re: LOSING POWER

John, I have a 91 Force o/b. I have experienced the same problem. I found a loose wire at the stator. I had to test each system to isolate problem. fuel/electrical/compression. Unfourtunately I found an electrical problem and low compression on one cylinder. Its very difficult to diagnos an intermittent problem. Good Luck