88 mercury 45hp

[ugadawg187]

Okay so the the motor will run but not idle. You have to open up the throttle to get it to crank & keep it goin. As soon as you back of the throttle it dies. Sometimes its kind of sluggish about going when you throttle up, it kinda sputters a bit but then kicks on up & seems to run fine. The other thing that has me scratching my head is that it will only run 4000 rpm at WOT & sometimes the rpms drop down to 3200-3500 while at WOT but it does not sound like the motor idles down at all when the rpms drop so thats prob a tach issue right?


Ive been told it could need the following:
1. carbs cleaned/ rebuilt
2. stator
3. trigger
4. rectifier

Heres a pic of some bad wiring on the motor that goes to the switch box. I believe its the trigger wires but not sure so let me know if im wrong. (black/white wire)

 

[BassnKY]

Re: 88 mercury 45hp

OK, first thing first.

Get all the wires fixed first. Then start with the diagnosis.

If you still have the problem after fixing the wires, which could be PART of the problem, I highly suspect rebuilding the carbs will solve the problem. When you rebuild the carbs, I would go ahead and replace the plugs as the can get fouled or over heated.

Good luck and keep us posted.

 

[ugadawg187]

Re: 88 mercury 45hp

Thats my plan but i need to know if this is a trigger wire & if i can cut out the bad part of the wire & replace with good wire or if the whole trigger assembly has to be replaced.

 

[BassnKY]

Re: 88 mercury 45hp

Without seeing a wiring diagram, I am not sure if it is a wire to the trigger. However, I had a similar problem on my 1984 Mercury 60. I soldered the wires together and used 3 layers (progressively smaller) of heat shrink tubing. This kept it from having a hard piece of wiring immediately transition to flexible which would end up breaking from vibration.

That exposed wire could be shorting out and causing a miss and possibly frying you switch box.

Always try to give the S/N on a Mercury so someone can look up the engine and diagrams to help.

 

[ugadawg187]

Re: 88 mercury 45hp

S/N - OB160951
its a 1988 merc 45 classic 50

 

[BassnKY]

Re: 88 mercury 45hp

Great. according to the attached/linked below wiring diagram, it looks like the white-black wire and it goes to the trigger.
Get this fixed and let us know how it goes.

http://www.maxrules.com/oldmercs/Wiring/1966ona/45MERC4_WIRING.gif

GOOD LUCK!!!

 

[ugadawg187]

Re: 88 mercury 45hp

Thanks BassnKY your alot of help. To fix this prob would it be best to cut the bad part of the wire out & splice new wire to it or try & put the heat shrink stuff on it? The wire already has some broken strands of wire some to me splicing new wire seems best but thats why im asking.

 

[BassnKY]

Re: 88 mercury 45hp

I guess the BEST way would to be the new trigger but I don't see any reason to go to that expense. Unless of course the trigger ends up being the whole problem.

As for splicing, I would solder/tin the joint and use the heat shrink (you can pick it up at home improvement centers in the electrical section). Just make sure to use 3 layers and try to have the smallest section at least double the length of the exposed wire.

 

[ugadawg187]

Re: 88 mercury 45hp

So can i pull the flywheel replace the trigger & put the flywheel back on without screwing up the timing?

 

[BassnKY]

Re: 88 mercury 45hp

I believe that is correct. Except for the larger engines, the ONLY way to adjust the timing is through the mechanical spark advance. Just be sure to use your repair manual (These are well worth the price) to set the correct torque and clearances.
Be aware that the trigger is attached to the trigger so be careful that you do not force anything.

 

[ugadawg187]

Re: 88 mercury 45hp

im confused on what you mean. do you mean stator?

 

[BassnKY]

Re: 88 mercury 45hp

Sorry about that (Brain fart). The trigger is attached to the spark advance linkage. But you will nee to remove the stator before you can get the trigger off.