1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

[hunter5411]

I Just Purchased A Used 1973 Evinrude 25hp And The Previous Owner Said The Last Time He Ran The Motor Was About 6mos Ago But It Ran Good?? Well I Just Tried To Start It For My First Time And After About 10-15 Pulls W/ The Choke Fully Out I Got It To Run But It Started To Back Fire Like Crazzy And Spit And Just Dies? Can Someone Plz Help Me To Get My Motor Running>> Thank You Soooo Much. I Only Purchased This Motor For $150 So I Knew It Prob. Have Some Issue And Didn't Really Even Know If It Would Even Turn Over. Well, I Was So Excited It Started But Like I Said Above It Just Won't Run W/out Backfiring And Spitting W/ The Choke Fully Out..

 

[tashasdaddy]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

shear flywheel key, you will have to use an OEM key. read removing flywheel, & coil and points. http://forums.iboats.com/showthread.php?t=299680

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

carb needs to be cleaned/pay particular attention to the needle valve.

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

clean the carb first before checking the flywheel key.

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

My Neighbors Ran Inside Scared Thinking I've Got A Loaded Gun!lol How Bout Plugs? Would That Cause My Problems Too

 

[bktheking]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

My Neighbors Ran Inside Scared Thinking I've Got A Loaded Gun!lol How Bout Plugs? Would That Cause My Problems Too

Sheared flywheel key, the timing is off, if the timing is off it will backfire. Pull the flywheel, replace the key, torque the flywheel and giver a try. You'll probably find the flywheel is loose as well. Had this exact same thing happen to one of my motors on the weekend.

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

I would replace plugs as well as a new water pump impeller and change the gearcase oil, as well as replace any fuel filter, if it has one.

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

Thanks Bk, Now Once I Remove The Flywheel How In The Heck Do I Mess W The Key And Adjust The Timing? Thank U So Much. I Really Want To Get This Running Soooo Bad. My Wife Is Giving Me Grief Telling Me I Got Ripped Off.. Haha

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

it may well be a flywheel key, and probably is, but I would do all these other things also including the carb cleaning.

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

Thanks Sparkie But I In The Heck Do I Replace The Key??? If Its Not To Much To Ask

 

[bktheking]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

Thanks Bk, Now Once I Remove The Flywheel How In The Heck Do I Mess W The Key And Adjust The Timing? Thank U So Much. I Really Want To Get This Running Soooo Bad. My Wife Is Giving Me Grief Telling Me I Got Ripped Off.. Haha

The key will be sheared, the key looks like a half moon. Half will be stuck in the flywheel notch for the key and the other half will be stuck in the crankshaft. Do you have the tools to do this is the better question? You will need a small punch, flywheel puller and the right size socket to remove the flywheel nut?


And oh ya, once you replace the key for $2 I'd hardly call it being ripped off, they get jealous when you start calling the motor "she" by the way

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

ROFL BK, I always try to call it an "it" just for that reason.lol as wifey could over hear you saying something about she was running hot, this can cause problems. and Hunter if the key is sheared it could be difficult to spot as it will fill the slots. also you will want to clean and or smooth out the area where the crankshaft and flywheel mate..also make sure you properly torque the flywheel nut or you will shear the key again quickly. once you have the new key installed the timing should be ok, but you can check it to make sure.

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

Well I Just Read The Top Secret File And I Guess I Have To Get The Harmonic Puller. Now Where Can I Get The Key From? Thank U

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

o yea..harbor freight has the flywheel puller for under $20

 

[SparkieBoat]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

local OMC dealer will have key..get 2 and keep an extra in the glove box.

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

Wow! This Sounds Waaay To Complicating I Might Have To Just Let A Dealer Do This... My Wife May Win After All!! Haha

 

[bktheking]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

Wow! This Sounds Waaay To Complicating I Might Have To Just Let A Dealer Do This... My Wife May Win After All!! Haha

BAH Now that's a defeatist attitude if ever heard one, don't you want to be Champion of the Outboard, this is how we prove the wives wrong man???? It's never rewarding to part with huge coin before Christmas and the dealer will laugh at you once they hear the year. Go get or borrow a puller and pull off the flywheel (if you live in Ottawa you can borrow mine!!), I can do it with a sledge hammer and a prybar but lets not get into you wrecking a crank. Pull the flywheel, tap out what's left of the key with a punch, put in the new key, borrow a torque wrench and torque it to spec. Once she fires up your wife will never forget the look on your face.

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

haha bk.. yeah ur right!! i'm gonna have to try i guess. now once i remove the flywheel is the key visible and pretty easy to replace? oh by the way i live in the sunshine state. tampa florida

 

[hunter5411]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

thank u for all ur help guys!! i'm gonna tackle this within this week and i'll provide a update w/pics of my motor running.. i hope! wish me luck

 

[bktheking]

Re: 1973 Evinrude 25hp *backfiring And Spits* Please Help!! Just Purchased Used

haha bk.. yeah ur right!! i'm gonna have to try i guess. now once i remove the flywheel is the key visible and pretty easy to replace? oh by the way i live in the sunshine state. tampa florida

Maybe Tiger has a putter HAHAHAHAHAHA I'm mean puller!


I kid I kid, see, if he had of worked on the outboards instead of.......well anyways back to your outboard.

This is what it looks like with the flywheel off.

That edge sticking out on the taper of the crankshaft is the key, only your won't be sticking out anymore, they are made of soft metal and shear if the flywheel is not torqued properly. Just for S&Giggles go and try and remove the nut holding the flywheel on, I'm betting it's loose.