1978 Mercury 1500 Black Max Choke Help Needed

[70Cougar]

I'm pretty sure the choke solenoid on the '78 Black Max 150 HP I recently bought is bad. I get 12 volts at the solenoid wire connection when the choke button on the control panel is pressed with the ignition in On / Run position, but the solenoid doesn't make any noise or click, so I'm pretty sure it's done for. My main question is how does this solenoid work, and what should be connected between the solenoid and choke plate? As seen in the picture below (sorry it's so dark), my solenoid doesn't have a linkage between it and the choke plate. I've found parts diagrams online, but none of them are very clear. If anyone has an actual picture that would be great! Otherwise a explanation of the linkage would be good. The solenoid has a hole in the end & when you look down it there's a cone looking piece with the pointy end up. I'm guessing that should pop out and engage the linkage?

 

[carholme]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

You appear to be missing the choke plunger which is the moving part when the solnoid is activated.

See item 34 in this link:

Mercury & Mercruiser Parts, CHOKE PLATE AND THROTTLE LEVERS, 150 H.P. XR-2 MARATHON MAGNUM (V-6) (1978-1985 COMBINED BOOK)

Gerry

 

[Maxz695]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

Yes the plunger appears to have fallen out or it,s missing. The coil inside the solenoid creates and electromagnet and pulls the plunger up inside of it when activated and pulls open the choke. The plastic arm on the plunger may have broken and the plunger slipped out. It must be set way up inside the solenoid or it will bind and not move to open the choke.

 

[70Cougar]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

OK well the plunger & arm are definitely missing then. Being that the solenoid doesn't actually move itself, should it be making any noise (clicking) or anything now? In other words, I'm wondering if my solenoid is OK & not doing anything since the plunger is not in there.

 

[carholme]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

If you have the 12VDC at the solenoid, you are not going to hear anything until the plunger is installed enabling the plunger to be drawn inwards as a result of the magnetic field created when the 12VDC is applied.

There is probably nothing wrong with the solenoid other than the missing plunger.

Gerry

 

[70Cougar]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

Great, thanks for the help everyone! Now I just need to locate the plunger / linkage used, since all the parts suppliers I've seen have it as Obsolete / No Longer Available.

 

[Maxz695]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

try ebay If I new the linkage set up I might be able to search it for you i,ll see if I can locate it quick

 

[Maxz695]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

don,t see 1 for a 1500 but heres link to get you aquinted with the aporoximate view of what they look like. Seach different words like Mercury choke Mercury parts (Boat barts etc) http://www.ebay.com/sch/i.html?_odk...570.l1313&_nkw=mercury+choke+plunger&_sacat=0 appears my ebay links have been disabled your gonna have to search it mercury choke plunger

 

[70Cougar]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

Thanks Maxz695, I believe some of those are the correct part though. '54283A 1' is one of the part #'s I found, and I also found somewhere that setup was used on Merc's 70HP and up from 1970 - 1982 or 1983. My buddy gave me the # of a guy who lives an hour or so away that deals in old outboard electronics. I might go up there tonight after work if I have the energy to drive a few hours, and that way I can pick it up in person & also see what all he has that I might end up needing later on.

 

[Maxz695]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

OK cool good luck with everything.

 

[70Cougar]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

Thanks for all the help! I'll post an update after I get it going. With some luck I can enjoy some fall fishing!

 

[70Cougar]

Re: 1978 Mercury 1500 Black Max Choke Help Needed

Thanks again for the help everyone. Got the choke back on. Funny thing is that I bought 2 different models of the plunger off the guy, after driving 4 hours round trip after work. Of course NEITHER one was right! I felt like the 3 Little Pigs b/c 1 was too long & the other was too short. Then, I accidentally dropped the shorter one & the plastic snapped. No wonder the guy had like 20 solenoids and only 4 or 5 plungers! It didn't matter anyway & I ended up rigging it, it is probably better than new. I removed the old & brittle plastic, pushed some shielded wire through, tied a figure 8 stopper knot, & looped it through the choke plate control, then secured it in place with 2 zip-ties.

Works great, but then after being eager to go on a shake down run it wouldn't start. I did a compression test & found all cylinders b/t 112-125 psi except 3 that had 0. The next day I went down after work & put my bore-light in the spark plug hole to find a hole in the bottom edge piston. :facepalm: Bad luck b/c it ran like a top when I went to look at it. So now it looks like the powerhead's gotta come off. Sucks, but oh well, when you pay a few hundred bucks for a 27 y.o. bass boat & 34 y.o. engine that a guy has to sell within a couple days before his dad junks it after he moves stuff like that happens. It will still be a great boat at a bargain price once I get it up and running tight.