what now!!

[rob711]

okay my 1984 90hp johnson starts easily first time...runs great for half hour..i shut it down...then its hard to start does not really want to idle and sounds rough...i've changed fuel filters, plugs rebuilt carbs..tried running it off portable tanks..each cylinder has 120psi...i've pulled each plug with it running on the muffs and the bottom two cyilinders dont really make much difference, although there is spark there..its just not as noticible as the top 2..does 2 stroke oil go bad...i'm still using the vro set up and i dont know how old the oil is in the tank...what else is there..spark commpression fuel should = good times...help

 

[tashasdaddy]

Re: what now!!

if pulling the bottom 2 makes no difference, are they getting fuel, you may be dragging dry pistons in the cylinder. your top carb feeds the top, bottom the bottom. sounds like a bottom carb problem.

 

[rob711]

Re: what now!!

i know u hate this ....i tried switching the carbs and the same results..there is change just not as noticable as the top 2..does the oil go bad...like i said it will start up cold no problem..once its warm it runs bad...i don't have the cash but i'm considering getting profrssional help....that is help with the motor!!

 

[jtexas]

Re: what now!!

"there is spark there" -- will it jump a 1/2" gap? (spark tester, couple bucks at auto parts store).

What do the spark plugs look like after idling? note any differences.

"does 2-stroke oil go bad?" not worse in 2 cylinders than in the other two.

 

[rob711]

Re: what now!!

good point bout the oil..i did not do a spark test...i'm hoping its not both power packs...but thats what i'm leaning toward..to me it seem electrical..i've had 2 stroke dirtbikes that did this..thanks for the advice

 

[rob711]

Re: what now!!

does any one know if i can use the power pack off a 110 hp evinrude on my 90hp johnson...i know someone that has what i believe is a 87..mine is a 84...maybe i can try that before i buy new ones

 

[jtexas]

Re: what now!!

you have one powerpack for the starboard bank and one for port, not upper & lower.

what about the spark plugs - do the bottom two look different from the top? are they wet or dry?

spark test just to be sure - if bad spark on the bottom, rule out coils by swapping with the uppers -

 

[rob711]

Re: what now!!

thanks j texas..i've been away..i cant get this off my mind....mostly because summer is slipping away and my boats not working...i have not done a spark test yet..the plugs are new and they all look the same...nice brownish...not oily..i also tried switching the coils top to bottom and port to starboard...i still lean toward elecctrical because it runs great when its cold....starts right up...idles..it idles a bit high because i tried turning it up on the water when this first happened..but after it warms up it seems like its barley running...i wonder if it warms up something that causes it to run like...sh&t...i relaize the power packs controll sides not top to bottom...thats why it seems odd that it would drop the 2 bottom cylinders seperatly...maybe some one else could try the cylinder drop test and let me know if the bottom 2 make any difference..as i said the top 2 will just about stall the engine..not so much for the bottoms..when this first happened and i replaced the plugs the bottom starboard plug was oily and fouled looking...but they all look good now...my b -day is comming and the wifey mentioned getting a new outboard...but this one seems like its something simple that i'm missing!!! thanks for reading

 

[hoeser]

Re: what now!!

If you throw out that engine throw it into my back yard. 120psi on all 4 on an 84 ' 90hp makes for a great engine. You need to do a proper spark test, 7/16" gap, strong blue crack.

 

[hoeser]

Re: what now!!

Did you clean the carbs when you had them off to switch them?

 

[rob711]

Re: what now!!

i know thats why i still have it...plus canada is far from long island!!..i'll get a tester tomorow..some elese said half inch...either way i'll do that and post my results