1996 mariner efi 150 power loss

jpohlman

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Joined
Oct 22, 2010
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14
i bought this boat 4months ago.it ran great,but it still had oil injection hooked up so i removed it useing manual and partslisted,i dont think my problem is related but might be so im adding that info.it started hesitating while running but only for a second and only once a trip,then it lost power on about the the 2nd trip after the removal.lasted 10mts,it acted like it dropped atleast 2 cylinders.now it does it every trip after running it a few minutes,it might clear up and run fine for a few minutes than cut out and stay that way till i get it back to pier,never does it cold and feathering the throttle gets it cleared sometimes but not every time.when it does this i do smell raw fuel and it does seem to foul plugs,,,but it is firing ,ive put in new plugs while its acting up and it will run a few mts and do it again.coils are firing and ive put on plug wires, all filters 3 sets of plugs.i cant figure it out,i thought it might be a weak fire but its firing blue.50;1 mix and bu8h plugs.the motor runs great but then this happens and thats it.when the boat is running good i can pull number 2 wire off plug and i cant notice a drop in rpm or sound change but the boat does lose power doing this . ive done this and than gassed i and it want pull but the number 3 cyl will shut the motor down when i pull it,so i moved that coil to the 2 position but no differance,might not be related.
 

jpohlman

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Oct 22, 2010
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14
Re: 1996 mariner efi 150 power loss

heard to many bad stories ,didnt trust it 14 yrs old
 

jerryjerry05

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May 7, 2008
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17,927
Re: 1996 mariner efi 150 power loss

1st thing do a compression test.Then a spark test.They OK then start with the fuel pumps.Manual pump take it apart see if the diaphragm is ok.
The electronic fuel pump take a pressure reading at the schrader valve. Compare that to the specs for that motor.
Post your results.J
What's the serial # ,it helps to find the right motor.J
 

jpohlman

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Oct 22, 2010
Messages
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Re: 1996 mariner efi 150 power loss

my discription might be a little hard to understand so i will simplelfy,seems to be getting fuel,fouling,seems to be firing hot,good spark and blue,but major power loss,i can guess its firing off time or timing issue but ive never had these problems occur sometimes,usually there constant but ive never had a efi marine motor.its like flipping a switch from perfect to a v6 becoming a 3cyl.and its never a pattern,its sometimes as soon as the engine runs 5 mts,or 20 minutes of driving,i can stop and fish while its acting up and after fishn 30 mts fire it up and its fine than 20 seconds after planing it does it,sometimes it does it as im planing ,and usually after the 2nd time it does it on a trip it stays that way,then i put it in the water a couple days later and start over again
 

jerryjerry05

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Re: 1996 mariner efi 150 power loss

Do the checks like I suggested.The basics on diagnosing is compression, spark and then fuel.
What's the serial# ? Get inline sparkies(spark testers) and run it while they are on.
It could be as simple and cheap as a loose wire or as expensive as a new electric fuel pump.
It sounds like the fuel pump is on it's way out.J
 

bullet 101

Seaman Apprentice
Joined
Aug 8, 2010
Messages
34
Re: 1996 mariner efi 150 power loss

My 150 is an 88 model and the oil injection is still operating
 

Faztbullet

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Mar 2, 2008
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Re: 1996 mariner efi 150 power loss

Make the problem happen and test it on the trailer. Take a timing light and check each cylinder for spark as it sounds like your dropping the high speed side of stator or a switchbox on one bank.
 

jpohlman

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Joined
Oct 22, 2010
Messages
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Re: 1996 mariner efi 150 power loss

thanks for the suggestions,i will try them asap and post results,ser #0g937264.i also took it out lastnite and in pitch black i can see it firing thru the porcelian on the plugs some look to be strong and others a little dimmer ,oh and glad to hear your oil pump works.
 

jpohlman

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Oct 22, 2010
Messages
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Re: 1996 mariner efi 150 power loss

im taking it out wed nite to check fire and fuel pressure
 

jpohlman

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Oct 22, 2010
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Re: 1996 mariner efi 150 power loss

the ser #is 0g397352 i listed the wrong boat above
 

fdhfdhaab

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Oct 28, 2010
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Re: 1996 mariner efi 150 power loss

your symptoms sound just like mine , i have a 95 150 efi doing the same thing.hope you have better luck than ive had.
 

jpohlman

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Joined
Oct 22, 2010
Messages
14
Re: 1996 mariner efi 150 power loss

took boat out tonite.ran 15 minutes and stopped to fish 15 mts,cranked to move and it was acting up as soon as it fired up,i idled about 5 mts to make sure it was gonna stay in it,it did so i tested fuel pressure at stem on vst tank,34 psi,also checked fire with timing light all 6 are firing same strength it seems,also before i left today i drained fuel and refilled and was careful to mix 50 ;1 accurate.i then idled about 100yds and it cleared up so i got on plain and ran 1 mile and it did it again so i stopped and put in fresh plugs and that did not help so i idled to boat ramp another mile and as i was pulling up to pier to tieoff it cleared up and when it clears up it is instant.so do i have a fuel injector clogging or getting a bad signal?or what else do i need to check.ive got fuel pressure ,compression,and spark so only thing i dont know for sure is if that fuel pres is getting to every cylinder rite?
 

Faztbullet

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Mar 2, 2008
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Re: 1996 mariner efi 150 power loss

Its possible you have a injector sticking and it will be hard to catch that problem. Have you tested/checked the TPS sensor? It it checks ok, send ECU and injectors to Brucatosvs.com and have cleaned and balanced and ECU tested.
 

jpohlman

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Oct 22, 2010
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Re: 1996 mariner efi 150 power loss

i live near birmingham al,i would be willing to pay someone to ride in boat and trouble shoot,all the local mechanics are on dryland and u cant get this boat to act up unless its ran awhile.
 

jpohlman

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Oct 22, 2010
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Re: 1996 mariner efi 150 power loss

anyone have a way to test tps without buying the wiring harness that the manual says you have to buy?the harness is 60$ and a new sensor is 60 $ haha
 
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jerryjerry05

Supreme Mariner
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May 7, 2008
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17,927
Re: 1996 mariner efi 150 power loss

The specs say the pressure should be 34-36# Does it stay at 34# while running or fluctuate? You can run it with the guage installed.
Try draining the VSP tank.Check the diaphram in the manual pump.Check for water in the fuel.
Try taking the injectors out there should be a filter on each injector.Might be clogging.
My 225EFI would do that and it was the stator going bad.But It really hated Ethanol.It caused all kinds of trouble.J
 

CharlieB

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Joined
Apr 10, 2007
Messages
5,617
Re: 1996 mariner efi 150 power loss

Its possible you have a injector sticking and it will be hard to catch that problem. Have you tested/checked the TPS sensor? It it checks ok, send ECU and injectors to Brucatosvs.com and have cleaned and balanced and ECU tested.

Clogged injectors screens will starve fuel and lean out that cyl.

Dirty, stuck injectors will squirt fuel, run rich, foul plugs.

Listen to Faztbullet
 

jpohlman

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Joined
Oct 22, 2010
Messages
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Re: 1996 mariner efi 150 power loss

i ran it with the gauge hooked up but with the jack plate my motor is border line submerged getting on plain and off so have to keep cowl on,but i pulled cowl and checked several times during trip and checked i justcoulnt during running on plane,it holds a steady mid 30s psi on pressure while running good and bad,my gauge is set to gauge in tens but its steady between 30 and 40 psi,ive replaced all filters and inside the vst,drained the system 4 times total,including fuel cell and vst,ive drained it twice since and no water present,i even added a clear microfilter before the vst so i could keep a eye on it.and the mechanical pump is performing as should,its keeping the vst full at all times,when i ran boat the other night as soon as it acted up i shut boat off and pinched the inlet fuel ine off so it wouldnt drain,drained vst and it was full,i will pull injectors and see what i can see from there,thanks to all and i will post results.when i say submerge i mean the back 4 inches of cowl is at or in water 6 in up back,but ve watched 50 other boats with jacks and they are the same,
 
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jpohlman

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Joined
Oct 22, 2010
Messages
14
Re: 1996 mariner efi 150 power loss

stater test,power pack test,fuel test,injector screens clean,im running out of things to test,,,im checking ignition switch next,,anybody got any ideas
 
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