75 HP Mariner ID info problems

[muskyfins]

Just got what appears to be an excellent condition 75 Mariner. Bought from a marina 300 miles away, but got a great deal on the rig. They started it for me and it ran fine. Shut off. Waited. Restarted. Ran fine. Dragged her 300 miles home. Tried to start last night and she won't start. No spark. (confirmed for cylinders 1 and 2. didn't check 3 and 4)

I didn't have the time to do a proper diagnostic per the manual and am going to order a new trigger today to have by the weekend. Do these triggers just go out instantly like that? Works one day then not the next?

The problem is there is a ton of conflicting info for what motor I actually have. I have checked all the usual places and found the following:

Mercruiser parts-serial number shows 3 cylinder. This motor is a 4 cylinder
Mercruiser parts-shows listing for 4 cylinder 75, but serial number doesn't fit series
autorepairmanual.biz-shows only that my serial number is a 1986 model year 75 HP
boatinfo-factory manual doesn't show any information for a 4 cylinder 75HP. Info shows for 3 cylinder 75 HP
boatinfo-non factory manual shows both a 3 and 4 cylinder 75 were available, but has nor part number info and limited tech info

So it seems to me there was both a 3 and 4 cylinder 75 made in 1986, with the 4 cylinder being rare. Can anyone confirm this? Is it safe to use the part number from Mercruiser parts . com for the 75 HP 4 cylinder even though serial number doesn't fit? See listing half way down list at link below.

https://www.mercruiserparts.com/sele...sp?type_id=MAR

I guess there's multiple questions in here. But I need to order it by 3 today to have by the weekend. I appreciate everyone's help and input.

Serial number 0B107494:help:

 

[Fun Times]

Probably a little late now but your engine comes up as an MARINER 75 ELPTO (1986) (4 cylinder) Serial No: 0B107494 Model No: 7075726 Parts Catalog No: 90-13289

http://www.mercruiserparts.com/selectDocs.asp?doc_nbr=13289
http://www.mercruiserparts.com/Show...r=40&bdesc=FLYWHEEL,+STATOR+AND+IGNITION+COIL

Service manual part number 90-86134--4 covers engine models,
75, 80 & 85 (4 Cylinder)
AND 90, 115 &140 (In-line 6 Cylinder)
AND 150 (In-line 6 Cylinder)
(U) 4590512 and Above (A) 8043775 and Above (B) 9139350 and Above (C) 7091098 and Above
(U) 4112635 and Above (A) 8027115 and Above (C) 7047258 and Above
(U) 4121435 and Above (A) 8028040 and Above (C) 7048783 and Above
90

 

[muskyfins]

It's never too late. I decided not to make a hasty purchase.

I was never able to find that manual number, so that's one problem. Thanks for the info.:high5:

I did find some diagnostic info on CDI Electronics' website and thought I should at least perform some type of diagnostic before getting ahead of myself. One of the procedures mentions whether there is a total loss of spark or only cylinder 1&2 or 3&4. So I thought I should systematically go thru all 4 cylinders for spark. I hooked up my spark tester to cylinder #1 and cranked. To my utter amazement, it had spark where there was none the day before. Put the boot back on the plug and on the second try, she fired right up!!!:whoo:

At least once per day, I will start her up and see if it is an intermittent problem or a one time thing. I'm not too worried because these are generally pretty reliable motors. Any ideas on what happened? I have two theories. #1-the "tilted too far" safety switch somehow was stuck after the 300 mile trip home or #2 One of the wires on the switchbox was shorted to ground and I moved it when I checked to make sure all connections were tight???:noidea:

Any thoughts are always appreciated.