1996 135 Black MAX loses power

[Gevans17]

I have 135 HP Black Max that runs fine for about 45-60 minutes. After that, it will not plane. Last 2 times out on the lake, I have returned to the dock at 5 mph. It will run fine at WOT, but after an hour or so, if I pull back to idle, then try to get on plane, no go. Then, advancing throttle does nothing, no increase in RPM above idle speed. Throttle can be advanced to WOT and engine is barely above idle speed. Then I have to idle in with what sounds like a slight miss.

Any suggestions appreciated. Also, you should know that previous owner (my brother in law)had his mechanic remove the oil injection mechanism several years ago as it never worked right. It has run fine on 50:1 mix until now .
Thanks guys for any help you can give.

 

[Laddies]

Re: 1996 135 Black MAX loses power

It sounds like the engine is losing 3 cyls. that could be either a stator or switchbox. You will need to test it with a DVA, possibly it won't show intill the engine is warmed up. By the way it sounds if it is losing spark to one bank like I think it is I would lean toward a stator, the engine trelly needs to be cked. as parts are very expencive. If that is the problem use CDI/Rapair parts for the repair, they are much better than OEM

 

[Gevans17]

Re: 1996 135 Black MAX loses power

Thanks for the reply. From reading this forum, this loss of power problem seems kind of prevalent with the Blackmax engines. Very frustrating to diagnose as it is intermittent. Why would a bad stator not be evident all the time, instead of only when the engine runs for a while?

 

[j_martin]

Re: 1996 135 Black MAX loses power

Thanks for the reply. From reading this forum, this loss of power problem seems kind of prevalent with the Blackmax engines. Very frustrating to diagnose as it is intermittent. Why would a bad stator not be evident all the time, instead of only when the engine runs for a while?

It's a temperature related failure.

 

[Gevans17]

Re: 1996 135 Black MAX loses power

I understand it is temp related, but how does that affect an electrical part like a stator?

 

[studlymandingo]

Re: 1996 135 Black MAX loses power

Is it possible it is in "limp home" mode?​

 

[Gevans17]

Re: 1996 135 Black MAX loses power

Well maybe it is..I have limped home twice now. What exactly is limp home mode and how can I correct it? Also, I should have mentioned previously that the boat was not used for 2 years prior to me buying it, except to periodically crank it up with muffs in the driveway. Of course, she runs great in the driveway.

 

[j_martin]

Re: 1996 135 Black MAX loses power

I understand it is temp related, but how does that affect an electrical part like a stator?

Electrical parts are made from a mix of different metals. Each metal has a different coefficient of expansion. As copper expands more than steel, it could expand enough to cause a short when hot, then retract and let the short go when cool.

Believe us, electrical problems are often heat sensitive.

hope it helps
John

 

[studlymandingo]

Re: 1996 135 Black MAX loses power

Some of these motors have a built-in protection that cuts power to the motor when it gets hot, it will allow you to run, just not with much power, keeps you from hammering it when it has overheated.​

 

[Gevans17]

Re: 1996 135 Black MAX loses power

OK, thanks for all of your help. The horn did come on the first time out for a few seconds, but after I shut it down for a few minutes, it never came back on. Cooling stream is present, but not forceful. might explain why I only have this problem after running for 45 minutes or so. However, the power loss has never occurred while running at WOT, but only when trying to accelerate from a stop.

 

[j_martin]

Re: 1996 135 Black MAX loses power

OK, thanks for all of your help. The horn did come on the first time out for a few seconds, but after I shut it down for a few minutes, it never came back on. Cooling stream is present, but not forceful. might explain why I only have this problem after running for 45 minutes or so. However, the power loss has never occurred while running at WOT, but only when trying to accelerate from a stop.

There are 2 low speed charge coils in that stator that supply spark when RPM is below a certain speed, I think about 3000 rpm. above that, 2 other coils supply the spark. If one of the low speed coils fails from the heat at WOT, you won't notice till you slow down.

Get ahold of a peak reading volt meter, and check the low speed charge coils at the switchboxes when it's acting up. Specs are in the book.

hope it helps
John

 

[Gevans17]

FIXED : 1996 135 Black MAX loses power

FIXED : 1996 135 Black MAX loses power

Cleaned carbs with Sea Foam, changed in line fuel filter under cowl. changed plugs, found and replaced corroded negative battery cable at battery ..........running like a bat out of hell now!