96 150 Merc NO POWER under load

[kevinclark93]

I have a 96 150 Merc carbed. I took it out and it would not get on plane and I could not get the rpm's up at WOT. After a couple of minutes the power and rpms came back. This has been an re-occuring problem and getting worse.

I check spark and the #6 cyclinder was not getting any spark. I tracked in back to a bad leg on one of the switch boxes. I have replace the switch box and the spark is back. I also replaced the fuel filter and got new spark plugs. I was hoping this would have fixed the problem but it is still there.

I am guessing it is fuel related. Where should I look next and how do I trouble shoot the fuel system.

Thanks

 

[kevinclark93]

Re: 96 150 Merc NO POWER under load

Took the boat out tonight and I can not get over 2000 rpm's in gear. It will rev up fine in neutral. Pumped the bulb while running and it had no effect. After that i replace the water separator filter. The was no water in the old filter, but there was a lot of debri, the gas looked mor like apple juice then gas.

I will take the boat out again sometime this week and test it out. I hope this will fix the problem.

Does anyone have any thoughts.

 

[kevinclark93]

Re: 96 150 Merc NO POWER under load

Okay i took the boat out again after changing the water fuel separator. Still could not get over 2000 rpms at WOT. Not sure what to do next. Rebuild the fuel pump clean the carbs I dont know. Could this problem be electrical???

I need some help!!!

 

[starcraft1982]

Re: 96 150 Merc NO POWER under load

Are you sure compression is good?Wouldnt hurt to check(or re check).Then,VERIFY youre getting GOOD spark to all six.After that,youll need to clean the carbs thoroughly.It sounds like you`ve sucked old gas(apple juice?)and debris into the carbs and clogged them.Also,debris has to come from somewhere so drain your tank,clean if necessary and replace your fuel line including bulb.

 

[kevinclark93]

Re: 96 150 Merc NO POWER under load

I have not checked the compression but i will. I will also get an inline spark tester and re-verfiy GOOD spark. I am still leaning towards the fuel system. I plan on checking it from tank to carbs and cleaning the carbs. I will let you know how it goes.

 

[Faztbullet]

Re: 96 150 Merc NO POWER under load

Sounds like you got a dead bank on stator, click link below and test stator...
http://www.cdielectronics.com/InstallSheet/174-9610K 2.pdf

 

[kevinclark93]

Re: 96 150 Merc NO POWER under load

Okay I checked compression and it is good on all cylinders. Between 105 and 110. I also rechecked the spark this time with an inline spark tester. Three of the cyclinders had good spark and the other three had none. The three that did not have any spark are the ones that are tied to the switchbox i relpaced.

I removed the new switch box and put the old one back on and the spark on that bank worked again except for the cyclinder that did not work in the very begining of all this. So just to clarify with the new switch box 0 out of 3 cyclinders work and with the old switch box 2 out of 3 work.

Is there something that could cause a switch box to fail or am I just unlucky and bought a crap switch box. I will get another switch box, but i want to make sure there is not something else causing it to fail.

Thanks for the feed back so far. The weather is getting good for fishing and I need to get on the water.

 

[Bifflefan]

Re: 96 150 Merc NO POWER under load

I just unlucky and bought a crap switch box.

Im going with,,,yep.

Thats my luck also. LOL, if it wasnt bad I'd have none..

 

[CharlieB]

Re: 96 150 Merc NO POWER under load

It is possible that the first box has a bad scr on #3, but it is also possible that the other box on the motor has a bad Bias circuit.

Continue troubleshooting, disconnect the bias wire (white) from the two modules and retest for spark with the new module installed. If you now have spark on all 6 then the Bias in the other old module is causing the 'no spark' on the new module and also needs to be replaced.

 

[kevinclark93]

Re: 96 150 Merc NO POWER under load

Thanks for the quick reply guys I will diconnect the white wire and recheck for spark. I will post my results.

 

[blay127]

Re: 96 150 Merc NO POWER under load

could accidentally grounding the switchbox to a power source and making sparks ruin the switchbox?