What year?

[Rugid]

I have some issues with my 105. So first thing I need to get to the bottom of is what year she is? Model # is 10576 I'm guessing late 70's

 

[Frank Acampora]

Re: What year?

Unfortunately I do not have my model number chart nearby. Your model number is early as later on they used a combination of numbers and letters like 105HC or 1056HC (example only)

Well, the cover has the release latch in the back, up top, and that is early. The lower unit drops straight down to the small cavitation plate and that is early. Later units tapered down and the cav plate was longer. (incidentally, these later lower units up to 1978 will bolt right on to your midleg)

The engine has Motorola ignition with the finned regulator but they used that up to about 1979-82.

However, the distributor is single wire points and that would place the engine around early 70s.

Year does not really matter with the block--they made the 105 forever and almost any part will swap into it. The only areas where it is important is if you want a specific part, like a rotor for your distributor, or lower units--you have a 2 piece lower and in 79 they redesigned to a one piece lower which will NOT fit your engine.

By the way: The block color is different than the midleg, shroud, and cover. That engine has the larger TC carbs. I don't remember seeing a 105 with TC carbs, most came with WB carbs. Are you sure that someone did not swap a 120 or even possibly a 140 block onto the 105 leg? Short of disassembling the engine there is no sure way to tell, howerver, there MIGHT be a stamped number on the back of the block up high next to the head. If you find this number and contact Mercury, they can access their database and tell you what block it is. One quick test though, would be to measure stroke through the plug hole If it is 2.875 then it is a 140 or 125. All others were 2.80 stroke.

 

[Rugid]

Re: What year?

Year does not really matter with the block--they made the 105 forever and almost any part will swap into it. The only areas where it is important is if you want a specific part, like a rotor for your distributor, or lower units--you have a 2 piece lower and in 79 they redesigned to a one piece lower which will NOT fit your engine.

Good to know about the block, but the 2 current issues I'm having are to do with the ignition and the drive gears.

By the way: The block color is different than the midleg, shroud, and cover. That engine has the larger TC carbs. I don't remember seeing a 105 with TC carbs, most came with WB carbs. Are you sure that someone did not swap a 120 or even possibly a 140 block onto the 105 leg? Short of disassembling the engine there is no sure way to tell, howerver, there MIGHT be a stamped number on the back of the block up high next to the head. If you find this number and contact Mercury, they can access their database and tell you what block it is. One quick test though, would be to measure stroke through the plug hole If it is 2.875 then it is a 140 or 125. All others were 2.80 stroke.

This makes sense to me because the previous owner claimed he swapped out the engine for a 150. I took it as a grain of salt so to speak because I didn't pay anything for the motor. So how would I go about to determine the year of the leg?

 

[Frank Acampora]

Re: What year?

midleg and lower unit are early late 60s-70s--no later than 75. See my private message about your slipping out of gear.

What is the ignition problem?

 

[Rugid]

Re: What year?

See this thread Frank http://forums.iboats.com/showthread.php?t=425322 Btw thanks for all the help.

 

[Frank Acampora]

Re: What year?

THAT, My friend is a most difficult symptom to diagnose! Even I have trouble with this one! Sounds like as the CD box heats up it functions better and that is opposite the usual failure mode.

The Motorola electronic CD box is completely potted in epoxy inside so smacking it should not shake anything at all. Basically it has a switching transistor and a couple of capacitors--that's why it is called capacitor discharge ignition.

At any rate, If something by some miracle is loose inside, because of the potting, it is not repairable. It does come to mind that the capacitors, being of wound construction may be defective, but again, nothing is repairable. Actually some people do repair these units but since only the case is salvageable, the repair costs as much as buying a good used one.

The CD box is mounted on rubber bushings so if you are smacking it hard enough you may be jiggkling the coil or wires. I would completely remove the unit from the engine--disconnect all wires, red blue white black etc. and check all wires for internal breaks. Check all the grounds to be certain there is no corrosion on them and remove the high tension lead from the coil. Clean the coil tower and lead and re insert the lead with some electronic grease.

 

[Rugid]

Re: What year?

That is what I thought immediately. A loose connection. But I checked all wires. Can the plug and coil wires be swapped out with automotive or another marine set? Since getting the originals are next to impossible. So now that I checked the wiring where do I go from here? As a side note I have power going to the black box but not coming out of it.