low idle miss 25hp evinrude

[scrubby1212]

e25tecte <br />e0268141<br />its an 1983 electric start 25hp evinrude<br />starts fine runs fine after u past 1/4 throttle into full throttle.but low speed miss <br />changed plugs cleaned carb took a different coil (its the top hole with the problem) didnt seems to make a diff.95 psi compression in both holes.seems to have good spark but wont run very long with the bottom wires off.will run just fine with the top wire off. i havent pulled the fly wheel off yet was trying to avoid that but will if i have to.all grounds look good havent tested volt readings on any thing yet need to get the book first.

 

[G DANE]

Re: low idle miss 25hp evinrude

Hi Scrubby1212<br /><br />Welcome to this forum. If you are sure compression is within 10 % on both cylinders, my best advise to you would be first to test ignition, by letting both sparks jump a 7/16" gap to ground while you cranck it by starter. You can do it simple by putting a nail in sparkplug boot and hold boot by an insulated plier. See to that both have the possibility to spark, by leaving a sparkplug in the one you dont test, and lay it to ground. Crancking without any possibility to spark, have a tendencity to damage powerpack by the big build up of current inside pack. If both jump gap at every spark with strong blue flame, rule out ignition. Then I would pull carb and take a look at reed leaves, one might have a chipped leaf.

 

[scrubby1212]

Re: low idle miss 25hp evinrude

ok this is what ive done since my last post changed the cdi had the coils tested checked the reeds and put in another set of new plugs<br />no change still miss fires at low idle to 1/4 throttle but seems to have intermitent at idle like it will catch then not i can always do another compression test thats no big deal

 

[G DANE]

Re: low idle miss 25hp evinrude

Does the fuel pump sit at the top cylinder bypass cover on this model ? If it does, I would check if it has a leaking diaphrame, flooding that cylinder a bit. Unscrew fuel pump from motor, squeze primer ball firm for a period and see if fuel drips out. Did you replace ignition components with new or from a part motor ? Dont just replace parts, unless they show faulty operation, it will only cost $ and confuse you, my advise is to troubleshoot instead. Cause for a bad running upper at iddle can too be shot upper cranckshaft sear, which will be visible by fuel/oil flowing down motor from stator area. Look for possibilities for airleaks affecting upper alone, bypass cover, etc. When did this start ? Did you actually gap-test spark ?

 

[sdiet]

Re: low idle miss 25hp evinrude

I'm having the same problem, won't idle but starts and runs good, otherwise. you might check my post "air in fuel line". I haven't done the rebuild on fuel pump yet, will post if it takes care of problem.

 

[scrubby1212]

Re: low idle miss 25hp evinrude

fuel pump sits on the side of the motor and it was a new in the box cdi no leaking from anywere that i can c i had my local marine guy that i have been dealing with for over a year gotten stuff from him for all my sleds and boats and have never had a problem when talking to the guy tested the coil he said the 1 im not having a problem with test lower then the 1 im having a problem with he said the coils were reed were good o and i just bought this motor and boat from a friend and he says it didnt have it last yr but who nows they are people that i trust for there word but

 

[G DANE]

Re: low idle miss 25hp evinrude

Test the fuel pump for leaking diaphrame, look for possible airleaks, change sparkplugs to 2 new champions and then I would advise you to do a iddle mixture adjustment, with boat moving freely in water, following steps in manual. Then let us know. How could your marinaguy tell reeds were good without examining them ? Did the spark gap test show both spark jump the 7/16 gap with strong blue flame ? We need some facts to help you out.

 

[scrubby1212]

Re: low idle miss 25hp evinrude

lol i took off the carb and the reed plate and brought it to him and ive put 4 new champion plugs in it then i went to ngk plugs from what i can tell doing the spark gap it seems to be blue and have good spark man sorry im not a boat mechanic but im learning but if this was a car it would be no problem lol

 

[scrubby1212]

Re: low idle miss 25hp evinrude

upon further inspection i do see some oil under the fly wheel on the motor