couple questions

[TMALEGA]

Hello everyone. I am new to boat repairs and am trying to fix the one main problem i have. It has me a tad confused though.it is on a 1985 85hp force outboard. SERIAL NUMBER IS 856X5LG

I have been reading on how to install a tach, i currently have one installed and it is stuck at 4000 and when i connect my battery it jumps and stays at 6000, i checked for the settings and cant find one. I have repaired the connections on it. So i guess my first question is.

1. Does this motor for sure take a 20 pole tach? I was told if it doesnt have a distributer it is a 12 pole and mine has 3 coil packs.

2. The red power wire going to the back of the tach doesnt go to the ignition it goes straight from the harness into the tach. Could that be a issue? According to my buddy i bought it from the tach was working last year when he put it up, since everything else he has told me on this motor has been accurate i have no reason to doubt what he says about it working last year.

3. If it is suppose to go through the ignition switch how could i fix this? The gauge wasnt doing anything at all but was stuck at 4000 rpms before i fixed the connectors. Now when i connect the battery even with the key off it jumps and sticks at 6000. I am trying to avoid taking it to the mechanic due to the diag fee and then if it is the tach i would need to buy a high dollar tach, or atleast that is what they offered me.

Thanks for any help you all can offer me.

 

[Frank Acampora]

Re: couple questions

NO! Distributor ignitions take a 12 pole tach. Your engine uses a 20 pole.

The tach should be wired with a power wire (usually red) from the "I" terminal of the ignition switch to the power terminal of the tach. This turns off the instrument when the ignition is off, preventing draining your battery. The PURPLE wire (in the harness or cable) is the signal and this wire should be attached directly to the signal terminal on the tach. Then, you should attach a black ground wire from the ground terminal to a good system ground.

If the tach supposedly worked last season, then you might want to check the voltage rectifier. A bad rectifier will affect tachometer operation.

Most 20 pole tachs do not have a setting switch, knob, or button, but some are multiple applications and do. If yours does have a knob or button on the back, "3" usually corresponds to 12 pole and "4" corresponds to 20 pole.

 

[carholme]

Re: couple questions

What p/n tach are you using at the moment?

Here is the parts list for your engine:

http://www.crowleymarine.com/mercury-outboard/1214.cfm

If you look under ACCESSORIES, you will see P/N 79-81703A1 as the
required tach. Though NLA at many sites, here is one which appears to be available:


http://www.plccenter.com/Buy/MERCURY MARINE/79817030A1.

Gerry

 

[TMALEGA]

Re: couple questions

So would that wire not coming off the ignition cause these problems? And how can i check the part you are refering to the rectifier i believe? I checked the wires and they are going to the proper place the only one odd ball was that red one coming straight out of the harness and to the tach. Sorry so many questions but i am trying to get a new prop and they want rpms and speed and all that good stuff. And as for the part number on the tach i am unsure it is old and there arent many numbers on it. I will see what i can find for it later this evening.

 

[TMALEGA]

Re: couple questions

Well i got the ignition switch wired into the tach correctly and yesterday i took it to the lake, sometime during which the tach dropped below the 4000 mark which it was stuck at. I read somewhere that hooking the battery up backwards can blow the rectifier. Which when i got this boat the cables were both black so i did do that. I have ordered a new and plan to replace it as soon as it comes in. But would that cause the tach to be constantly at or around the 4000 mark? Also got my volt gauge wired into the circut. That is how i know the tach is now wired into the system correctly. It is wired before the volt and after the switch. My only other question at this time is what is the orange wire that is coming out of the harness it is a solid orange wire and isnt connected to anything at all. I know pictures would help but it was dark when i got the wirig done and noticed the wire. Can i look back at the engine block and see what the orange wire is connected to would that be what it is for at the dash? All the tips has really helped out thank you all so much. I hope the new rectifier is what is going to fix my tach issues. I would so love a new prop to get the max out of my boat.

 

[carholme]

Re: couple questions

Look at the item 74 in this link:

http://www.crowleymarine.com/mercury-outboard/parts/1214_50.cfm

and you will probably find the orange wire connected to it, if it is hooked up. It is the thermoswitch for overheat warning.

Gerry

 

[TMALEGA]

Re: couple questions

Ok i looked at the wire and sensor you were talking about carholm and the sensor is broken the wire is melted so i repaired the wire now i need to find the sensor. Anyone know where to look for one all i have found is a bunch of discontinued places. Can i take it to a auto parts place and get something from them? Or is there another way of getting this fixed? Also the coil pack rubber mounts are broken or atleast 2 of the 3 are i have them zip tied to keep them off the wires below it. Are there replacement mounts available? I cant seem to find them either. I may just be blind tonight. Lol thanks again you guys are more help ful then the guy i paid to look at the motor a few weeks back.

 

[carholme]

Re: couple questions

If you look at the parts listing I sent you under Accessories you will see F5H043 | BUZZER KIT which is still listed as available at Crowley.

For the rubber mounts, item 42 in this link might be the size you are looking for:

http://www.crowleymarine.com/mercury-outboard/parts/1214_10.cfm

If so, they are available here:

http://www.marineengine.com/newparts/part_details.php?pnum=MER25-F475504&ptype=&Engine=&Model=

Gerry

 

[TMALEGA]

Re: couple questions

This may end up being a dumb question but does it matter which acc terminal the purple wire goes on, on the rectifier? Being if it isnt working on one side could i put it on the other side and see if the tach changes? I have a new rectifier coming in the mail sometime next week. I just didnt know if this was a possible test of the tach? Also i bought new plugs today and they dont have the normal design are the plugs for this motor the ones that are flat topped? Thanks again guys

 

[TMALEGA]

UPDATE couple questions

UPDATE couple questions

Got the new rectifier put on today have not taken the boat out yet and cannot hook muffs up to it since i live in apartments. So i guess my question is this should the tach have gone back to zero now or do i need to actually start and run the motor? I know it sounds obvious but i havent had the right thought process on things today and need to run it by you all. Thanks again.