Motor "Missing" how to fix?

[scramblerdude]

i have a 1975 25hp Evinrude that has not been run much in the last 5 or 6 years. It seems to have some kinda "miss" but only at higher RPMs, it idles fine and i trolled with it for about an hour....no problem but once i throttle it up it starts the missing thing. Any ideas?

God bless,
Chris

 

[larky]

Re: Motor "Missing" how to fix?

clean the carb(s). to do a complete job you need to order a carb rebuild kit.
read this link:
http://forums.iboats.com/showthread.php?t=244013

and this one:
http://forums.iboats.com/showthread.php?t=158086

 

[F_R]

Re: Motor "Missing" how to fix?

Would you describe this alleged "miss" as feeling like you hit a submerged object every so many feet or yards? That is not a miss and is a worn out clutch dog in the lower unit. The worn parts force themselves apart under load, the motor comes out of gear, rotates one half turn and instantly slams back into gear, giving you that kick in the pants. You can usually, but not always, see a jiggle in the gearshift (on the motor) when it happens.

 

[ragtop69gs]

Re: Motor "Missing" how to fix?

Would you describe this alleged "miss" as feeling like you hit a submerged object every so many feet or yards? That is not a miss and is a worn out clutch dog in the lower unit. The worn parts force themselves apart under load, the motor comes out of gear, rotates one half turn and instantly slams back into gear, giving you that kick in the pants. You can usually, but not always, see a jiggle in the gearshift (on the motor) when it happens.

Not meaning to hijack your thread scramblerdude but,

I think F_R is describing perfectly what my '82 Johnson
J35ELCTS is doing. F_R are there any checks to be done to verify a worn clutch dog Before I tear into it? The engine runs like a clock with the water muffs at all RPMS but in the water it's as you described.

A compression check showed 155 psi on both cylinders.

Others have ventured a guess that I had an air leak in the fuel line or a bad coil, but F_R nailed the symptoms I have. Any chance the others may be correct ?

F_R I could start a new thread if you would prefer. Thanks for any imput you may offer.

Thanks, Jay

 

[scramblerdude]

Re: Motor "Missing" how to fix?

Would you describe this alleged "miss" as feeling like you hit a submerged object every so many feet or yards? That is not a miss and is a worn out clutch dog in the lower unit. The worn parts force themselves apart under load, the motor comes out of gear, rotates one half turn and instantly slams back into gear, giving you that kick in the pants. You can usually, but not always, see a jiggle in the gearshift (on the motor) when it happens.

F_R, thats exactly whats going on. We changed the lower end with one we bought used and still have the same problem. Sounds like maybe we should just have it rebuilt. Thanks for the Info!

God bless,
Chris

 

[ragtop69gs]

Re: Motor "Missing" how to fix?

Chris, thanks for letting me piggyback your thread.

F_R thank you for your help. all your other postings on the clutch dog failure have given me a much better understanding of the problem.