1999 200hp intermittent lose of power.

[Bob1101]

Re: 1999 200hp intermittent lose of power.

Ran test on motor today and this is the results. All trigger wires tested at approx 1200ohms and 4v (DVA). High speed stator 31ohms and low speed stator 2100ohms. Stator DVA readings....blue 200v, red 80v, blue/wht 170v, red/wht 90v. All 6 coil ohms were approx 860 ohms and 0.04ohms (depending on orientation of meter leads). DVA reading at individual coils was sporadic and inconclusive but DVA reading at switchbox posts (leading to individual coils) was 130 on all post. My interpretation is that the trigger and coils are functioning properly and that the stator is faulty??????

 

[Bob1101]

Re: 1999 200hp intermittent lose of power.

CharlieB, removed idle stabilizer today. This is my wiring diagram.....grey/blk wire comes from top left post of each switch box and goes to detonation module; 3 wires come from idle stabilizer, blk to ground, brown/wht to top right post of outer switchbox; 3rd wire intersects one of the grey/blk wires mentioned above. When 3 wires disconnected from idle stabilizer no change noted in engine performance. Then disconnected 2 grey/blk wires and motor runs better than ever. Is it okay to leave all these wires disconnected? Oil alarm module has the ability to reduce rpms when problem detected, does it accomplish this via grey/blk wires that were disconnected or via CEU. I don't want to disable any alarm protection devices....... CharieB, thank you very much for your suggestion. Thanks everyone.

 

[CharlieB]

Re: 1999 200hp intermittent lose of power.

.............Then disconnected 2 grey/blk wires and motor runs better than ever. Is it okay to leave all these wires disconnected? .........................

You can safely disconnect and tape off all wires to the idle stabilizer module.

I am not sure which these blk/grey wires are.

The switchboxes have a Bias terminal on the top left with a White (?)Black trace) that must be connected to each other. If this is the wire that you disconnected and it now runs better then there is a problem with the Bias circuit in one of the switchboxes.

If so, Replace BOTH switchboxes.

 

[Bob1101]

Re: 1999 200hp intermittent lose of power.

Okay, it has been about 1or 2 mths and previous problem( not getting on step and very rough idle) is not an issue . Motor has power to get up and idle is very smooth but motor now has no power below about 2000 rpms. Motor not firing on all cylinders below 2000-2200 rpms . When rpms reach 2000 ish power spikes and boat takes off....spark test revealed no fire on cylinder #3, I changed switch boxes and problem followed the switch box, now no fire on cylinder #4. DVA output on green/white post 0 and all others appox 130_140. ........This is the confusing part. Previous problem ( not getting on step and rough idle) was fixed by removing the idle stabilizer and the detonation module, removing the idle stabilizer had no effect on motor performance but removing the detonation module improved previous problem. Now when detonation module is reinstalled new problem is fixed and I now have fire on all cylinders. Also note that with detonation module installed the DVA output on switch box post have a much broader range 100-160 and note that "previous problem" does return......Switch box problem? Detonation module problem? Both?

 

[CharlieB]

Re: 1999 200hp intermittent lose of power.

Merc/Mariner built these motors for many years using ONLY a stator, triggers, switchboxes, and coils.

Idle stabilizer and Detonation control are not necessary and are another possible failure.

If you had 'no spark' on #3 without the detonation control installed then there is a problem with either the trigger or the switchbox, or possibly a poor ground ono that coil, or a poor plug wire.

Likely NOT the trigger as #4 shares that trigger and was sparking.

Clean all coil grounds, ensure all plug wires have a clean solid connection to the coils.

Retest to confirm the 'no spark'. If you did switch the boxes and then 'no spark' on #4, then highly suspect that switchbox has an internal fault.

Is this a new box, still under warranty?

 

[Bob1101]

Re: 1999 200hp intermittent lose of power.

Finally had time to order switch boxes and install. Motor runs fine now. The detonation module was causing very erratic DVA readings , erratic spark at individual cylinders, making diagnosing problem difficult. Once detonation module removed dx was more obvious. DVA readings on one switch box were 142 on all 3 post, the other switch box readings were 120, 0 ,132. 0 reading leading to spark plug with no fire. Stator/trigger ohms and DVA readings good. Thanks to everyone again for your replies.