1987 110hp running rough

[boltdude73]

hello all, i have a 1987 110 (bubble back), last week, after adding sea foam to my tank, i went out for our weekly fishing trip,she ran like a champ as always until, after trolling around for a couple of hours, i opened her up to run back to the ramp. this is where i begin to have trouble, it seems like i was only running on three clyinders, so being cautious as i am, we put her back on trailer. came home pulled plugs, they didn't look that bad, but i still replaced them, gapped at .035, also not related to problem replaced water pump. took her out again today, she ran great, smoothest it has ran in long time, until we were coming back to ramp same problem, running rough seems like it is cutting out, pulled plugs again three out of 4 were wet and black, i'm at a loss as what to do next, can anyone help? i'm kinda stuck because i cannot find anyone around me that still works on outboards.

 

[2Smokinya]

Re: 1987 110hp running rough

Sounds like a cylinder is dying out, run it back at your house (with water of course) and pull off the plug wires (with a rubber handled plier) of every cylinder one at a time. If you pull a wire off and the engine is running the same as before, that tells you that there is a problem and that cylinder isn't firing.

 

[HighTrim]

Re: 1987 110hp running rough

What you should do next is perform a spark test. Do you have an inline spark tester? If not you can pick one up for about 10 bucks. Set the gap on it to 7/16 of an inch. It should jump it on all cylinders with a strong blue ZAP!! If there is a cylinder not firing, or firing weakly, swap the coil with one from a cylinder that is firing, if it now fires, replace the coil. If it is a bank, either port or starboard, that are both not firing, swap the power packs. If the problem follows the power pack, it will need to be replaced. You could also test the diodes in the power pack, do you have a multimeter? Even better a DVA?

 

[HighTrim]

Re: 1987 110hp running rough

Also what plugs are you running, they should be QL77JC4 or QL82C Champions gapped to .030, and torqued to 18.5 to 20.5 ft/lbs.

 

[boltdude73]

Re: 1987 110hp running rough

ok here goes, i checked the spark today, good blue spark that did jump 7/16" on all cyl. so i fired it up ran really rough for a few then smoothed out, then rough again, i found that a small wire on one of the coils did have a little bit of crud, but not bad though, i am at a loss!

 

[Solittle]

Re: 1987 110hp running rough

If you are getting spark lets look at fuel. Next time out when it starts to run rough squeeze the primer bulb a few times. If it smooths out you have a fuel system problem.

 

[boltdude73]

Re: 1987 110hp running rough

ok guys thanks for all the help, i decarbed motor last night, i will be taking her out after work today, i did get a little bit of carbon out not too much. i used Deep Creep, did it three times, as directed. seems to be running better, i did notice some air bubbles in sight glass, going to look in to that before i take it out.

 

[boltdude73]

Re: 1987 110hp running rough

up date , everyting seems to be ok, still not sure what fixed the problem, no i have a question, i have a 20 gallon tank, it was half full, after running on muffs maybe a total of 1 hour, it used it all, i mean all, this thing was bone dry, that is where i was getting my air at. just curious as to why it used so much gas?