Replace Ignition Solenoids on 8.1/496 Mercruisers

KevinC

Well-Known Member
Feb 25, 2011
3,813
Long Island, NY
Boat Info
2004 340 Sundancer
Engines
Twin 8.1 V-drives
So this spring my ignition solenoids were acting up. The typical symptoms are when you are trying to start the engine and you have to push the start button numerous times only to finally get the engine to bump and turn over. In all honesty, I started to notice this problem when the boat sat longer times towards the end of the season - so it was already high on my to-do list for spring commissioning. Now this spring after uncovering the boat I decided to try to bump the engines and it took something like 20+ pushes (each time hearing the click) before I go the bump of the starter.

Since this has come up for discussion a couple of times I figured I would post it here for others as it is a relatively simple repair. On a scale of 1-10 I would put this at a 2 (real easy) - checking oil would be a 1 ;).

Pictures to follow...

-Kevin
 
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So you have this problem and want to attempt the simple fix. Lets first see where you are going to locate these solenoids. On many engines they are right on top but in the case of the 8.1/496 they are a little hidden.

When looking at your cover they will be mounted to a bracket roughly within the location boxed off here:

ignition_solenoid_01.jpg

The cover can be removed easily by taking out three long screws. Before going any further I would make sure that all DC power is turned off to the engines.

-Kevin
 
Once you have the cover off you will see the bracket holding the engine computer and relays. The solenoid is attached to this bracket and hidden on the underside as indicated by the arrow.

ignition_solenoid_02.jpg

We will need to remove the bracket. To do this you will only need to remove the three nuts shown to loosen the bracket.

Here is a better view of the solenoid hiding below.

ignition_solenoid_03.jpg

-Kevin
 
Again - making sure your DC power has been turned off.

Once you have removed the nuts holding down the bracket you will be able to turn it to see underneath. If that harness is a little tight you might want to disconnect the computer - however in my case there was no need to.

Once you can get to the backside of the bracket you will only need to remove the two nuts shown holding down the solenoid. You will also have to remove the insulator on the top of the solenoid by gently spreading the sides as it is just clipped on.

ignition_solenoid_04.jpg

-Kevin
 
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Once your solenoid is free of the bracket you will need to remove the two nuts at the top. To remove the primary feed.

ignition_solenoid_05.jpg

The two thinner trigger wires were just push on connection that were held on by tension. I just needed to pull them up.

To keep things organized I moved one wire at a time.

-Kevin
 
After replacing the solenoids I quickly reconnected power to the engine, turn on my ignitions and the engine bumped on the first push. I then disconnected power again and reassembled in the reverse order. One thing I did was spray the solenoid with some corrosion guard before putting back the insulators and completely reassembling.

I also used genuine Mercury/Quicksilver solenoids. These are relatively cheap so it was NOT worth picking some knock-offs up on Amazon or Ebay. In fact, I picked up a third and now have my spare.

Solenoid Part Number: 89-96158T

If your experiencing this issue there is no need to put it off doing this.

-Kevin
 

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  • ignition_solenoid_06.jpg
    ignition_solenoid_06.jpg
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Great write up -- thanks for sharing!

Here they are on the 5.0 (5.7) with the cover removed:

upload_2022-5-6_10-50-57.png
 
This is awesome...Thanks! I am having this exact issue. Unfortunately I replaced the starter first only to figure out this was the issue.
 

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