1987 Force 125 missfires under load

[herb]

Cant tell if it does it all the time.Compression is 140 to 145 on all cylinders.Carb bowls look clean but I did not disasimble further.Should I check carbs further or check ignition?I installed new spark plugs.<br /><br /><br /> Thanks,Joe

 

[ODDD1]

Re: 1987 Force 125 missfires under load

Herb, which plugs? Are you running booster gap plug? side electrode or surface gap?

 

[herb]

Re: 1987 Force 125 missfires under load

ODDD1,the plugs are champion surface gap.<br /><br /> Thanks,Joe

 

[herb]

Re: 1987 Force 125 missfires under load

ODDD1,I just checked for spark and found that it will fire up to a half inch gap on all for cylinders.could it be a fuel or carb problem.<br /><br /><br /> Thanks again,Joe

 

[sony2001]

Re: 1987 Force 125 missfires under load

Your plugs should be Champ UL18V or<br /> NGK BUHX<br /><br />------------------

 

[ODDD1]

Re: 1987 Force 125 missfires under load

Herb, the reason i ask is the older force ignitions were'nt quite powerful enough to fire a booster gap plug..like the BUHX....i do not know if the UL18V is a booster gap or not.........the engines with black ign. boxes and coils were ok....the blue ign. coils and boxes were the problem...for those run a {NGK} BUHW for hard running and a {NGK} B9HS-10 .040"gap for fishin/trolling.<br />The symptoms of these blue ign. with a booster gap plug is...run ok anywere except wide open..the hotter the engine gets the worse the prob is..some run fine cold but after a run they fall off on the top end...this can be a sneaky prob ...thats why i made mention...yeah...dont neglect fuel ..could be trash in carbs..stretched fuel pump diaphram....anti syphon valve in built in fuel tank?

 

[herb]

Re: 1987 Force 125 missfires under load

ODDD1,the coils and boxes are the black one's.The plugs that were in it were the buhx.I installed the champion ul18v plugs.They do not have a gap.Is that a booster plug?If the proplem is that will it do damage to put the plugs that you gap at .040 in it?I have a clear filter in the fuel line and don't see any water or dirt.The problem devoloped after the engine got hot a 4500 rpm's.This boat is new to me and it was the first time out so I have no history on it.<br /><br /> Thanks for the help,Joe

 

[ODDD1]

Re: 1987 Force 125 missfires under load

Herb a booste gap plug and a surface gap look the same externally...booster gap have an add'l air gap INSIDE the plug,supposedly to increase the firing threshold and reduce fouling....but you need a HOT ignition to run em..the blue boxes come up a little short in that department. yes you can run the side electrode B9HS-10...just avoid all day wide open throttle....lol...get a fuel pump diaphram and gasket and change it just as maintenance it may be all your problem.....

 

[herb]

Re: 1987 Force 125 missfires under load

ODDD1,just one more question;would the stator,trigger or boxes cause a problem like this or would that be all the time.<br /><br /> Thanks,Joe

 

[ODDD1]

Re: 1987 Force 125 missfires under load

stator goes down you loose 2 or 4 culinders all the time....box can take out any 1 or both on that box a trigger will take down 1 at a time....i have seen triggers make this problem..they have very fine wires and they break inside the shrink sleeve at their connectors GENTLY tug on the wires..if they are proken they will slide right out of the shrink sleeves.

 

[sony2001]

Re: 1987 Force 125 missfires under load

Herb,you probably didn't run the engine at<br />max RPM with the old plugs. Try them! There<br />was a comment a few pags back that the quality control of Champion plugs is sinking.<br /><br />------------------

 

[herb]

Re: 1987 Force 125 missfires under load

Thanks ODDD1,now I know what to check for.<br />Sony,I have only ran it with the ngk plugs.<br /><br /> Thanks,Joe