Spark plugs for 91 50hp Force?

[shindig888]

Hi all! Would appreciate some info on the plugs I need for my O.B. The manual says...Champion UL18V usa or QA76V canada.... I've looked alround and cant find an exact match/replacement. The conversion to NGK is BUHX and of course the closest match I can find is a BUHW. When I cross ref. back from BUHX to champ I am told its a champ. L76V. now upon checking champ. numbers "QA" means resistor but after doing full loop "L"76V is not resistor, nor is NGK BUHX... And BUHW is a tungsten electrode... <br />QUESTION: what heat range am I looking for?.. 18 or 76 in a champ plug? Iam considering trying one up on the plug heat as I am wet fouling really bad, when I troll @ idle.

 

[jasper astro]

Re: Spark plugs for 91 50hp Force?

ShinDig...<br />NGK 2522 BUHX <br />1989-1991 50 HP FORCE MOTOR...all models<br />Just put a new set on my 1990, seems to be a improvement from the Champion plugs I took out.<br />Look for post, "spark plug question" further down the thread list.<br />Note eurolarvas post showing powerhead link, this plug is cross referenced to the Ngk plug I noted here...jas....petey....

 

[shindig888]

Re: Spark plugs for 91 50hp Force?

Thanx for the reply jasper. I picked up a set of NGK's from napa the other day. Heres a little story: As you know these are face gap plugs, so I am having "loading up" problems, so I remove the previous Champ. plugs and put them in my cordless drill and spin them against some scotchbrite to polish them up, and then i'm good for another day of fishing... engine starts, idles and runs full out great. then after trolling at idle "pretty much" for an hour, she starts to miss and run crappy. put it in neutral then high rev it to clear it out, at which time it starts to miss and race a bit as though its lean? then back in gear and off we go till it loads up again after a shorter time. after getting home the plugs already have build up, kind of sticky. then the next outing halfway through the trip she starts missing and runs like crap. limped the boat home. turned engine over with plugs out to check spark seems ok, maybe one lighter blue. thoughts of dread cross my mind...electrical? Changed to an other set of "polished" used plugs put her in the barrel ran good but loaded up so I turned the Idle mix screw in to 3/4 turn out and it idled fine and sounded pretty good. next day bought new ngk plugs put them in, packed up whent to the chuck started her up and she ran the ****s.. would barely idle and poped and farted at full throttle in gear. good thing I brought the previous plugs, put them in and she ran fine, till it loaded up again an hour or so of trolling...to make a long story short I think i got a bad ngk plug? have to do more investigating... will get back... My guess is that its not a great trolling motor.Is 3/4 turn on the idle mix too lean? the last set of plugs were a bit gooey and quite fouled still.<br /><br />P.S. Jasper, any luck on running your force OB?

 

[jasper astro]

Re: Spark plugs for 91 50hp Force?

I would have the coils checked. Everything you have said points to the fire. The plugs are supposed to be sicky, being your 50-1 fuel mix will cause this . Its better to run alittle more rich than lean. You may have a bad wire off a coil or off the power pack. You are getting spark, but maybe to little. Defenitly electronic at this point, seems that way. Hope Eurolarva reads this, he will have a better idea what to diagnose.<br />My 90 50 hp is waiting on its prop. Ordered it Saturday off this website and it still has not been shipped. Paid extra to get it here on Friday.<br />Everything is going well, just waiting....jas....

 

[shindig888]

Re: Spark plugs for 91 50hp Force?

So yesterdy I put another set of NGK plugs in my OB and run it in the water barrel and it would not idle very well and running in gear w/o the prop on @2500rpm it was quite rough. So I put an old set of "polished" champs in her and run it the same and it ran well... So then I put a set of BUHW plugs in and it seemed to run ok. Took the boat down to the chuck and it would not idle, as though it was only one cyl... rammed her in gear and went fishing any way. I rigged up a trolling bucket and was able to troll at a slightly higher rev (1100) and that was fine, no hesatation for the whole day but when I put it in neutral she wouldnt idle, or was sporatic...P.M.O.! anyway.. got home pulled plugs and they were pretty good. I have no idea why it has started to run like this. It's been gradually going down hill for the last 5 outings. How can I check the coils and ignition? The old QL76V and L76V plugs seem to work better than new NGK's<br />P.S. caught a 10 pound spring btw.

 

[eurolarva]

Re: Spark plugs for 91 50hp Force?

This sounds more fuel related then spark plug. Have you rebuilt the carb and the fuel pump? Probably crap in carb. I rebuilt mine two years ago and am having similar problems. It seems gas these days or changing from one outboard oil to another makes these carbs real touchy