Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Again..

[hunter5411]

ok i got the backfiring solved but now the *NEW problem i have now is , when i give trottle the part under the flywheel that engages to give trottle to the carb doesnt go all the way to push the cam looking roller down at all. it stops at mid point and never goes far enough to the point where the knotch gets wider. i hope im explaining this right

 

[psteurer]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

Is this motor the 1973 25hp Evinrude you described in an earlier post?

I think I understand what you are writing. When you have the throttle in a wide open position, is the throttle plate in the barrel of the carburetor exactly flat? So when you have the throttle in neutral, the plate should be closed and when the throttle is wide open, the plate should move about 90 degrees. Sounds like you need to do a link & sync.

 

[hunter5411]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

yes this is a 1973. i think i understand what u r saying , the last round piece under the flywheel has a notch that gets wider as u give trottle, but when i give full trottle it only goes half way and never gets to where the notch gets wider to push the cam on the carb..

 

[bktheking]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

What was causing it to backfire?

 

[hunter5411]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

bad carb.. the key was not sheared. i tell u what taking that flywheel off was one of the hardest thing i've done!! haha did u read my new problem i have now

 

[bktheking]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

It get's easier as you do a few. Like psteurer said you need to do a link and sync, should be in the service manual.

 

[hunter5411]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

how hard is that?

 

[psteurer]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

Link and sync is not hard but you really should have the manual for this motor since it will outline a step by step procedure to accomplish it.

I do not think you understood what I said in my earlier post. Look down the barrel of the carburetor and that is where the throttle plate is located. It is a silver roundish disc a little over 1 inch in diameter. It should be completely closed when you are in neutral and it should be flat inside the barrel of the carburetor when you have the throttle wide open. That is part of the link in sync process. If it not flat, then that could explain why the cam is not advancing as I think you are describing.

 

[hunter5411]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

yeah, i understand now and none of that happens. i wish i can explain what i'm talking about. its really weird because it never had this prob before. i'm gonna try to kinda explain myself a little better, the last part under the flywheel that turns when u give trottle has a bolt on plate that gets wider, well when u give trottle that whole unit turns and that little plate that is mounted to that part that pushes the cam downward never gets to the cam to push it down. so when i give it trottle its still in a neutral position. WOW! how confusing. i'm so sorry for this post, i wish i had a video i can post on here to show what i mean....

 

[psteurer]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

If the plate inside the carburetor does not move when you advance the throttle, then you definitely need to do the link and sync. It is possible that when you removed the carburetor to clean it, the linkage on the carburetor got out of alignment so to speak. I really do not know your motor well enough to give you further advice on the link and sync. There might be a screw somewhere on the linkage arm that will allow you to make an adjustment. But there might be more to it than that. If you do not have a manual for this motor, you really should get one. It will pay for itself in your first repair.

 

[lindy46]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

That cam is held on by 2 bolts, and needs adjustment. Loosen both bolts. At the skinny end of the cam, there should be a mark (or 2). With the throttle at the "stop" position, the cam follower (roller) shouldn't touch the cam. As you advance the throttle, when the roller hits the mark(s) on the cam, the throttle plate should just start to open. Adjust the cam so that happens. As you advance to high speed the cam follower should continue to open the throttle plate until it is fully open when the throttle is fully advanced. Pull the starboard end (fat end) of the cam out until this happens. Then re-tighten the bolts.

 

[kbait]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

A '78 has a rod that opens the throttle from about halfway to full throttle, and it links to the armature plate on the port side and has an adjustable stop. Not sure if a '73 has that, but that'd jibe to your description if the stop wasn't secure.

 

[perkdp]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

sounds like the "neutral throttle safety" is hitting the stop
or the arm from the throttle handle up to the timing plate is disconnected.

if you don't have a manual go here http://www.boats.net/parts/search/parts.html
select your motor and look at the pictures.

 

[perkdp]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

oh..... i failed to mention ... there is a rod coming down from the cam follower and one coming up from the carb. there's a clamp and screwn that join these together.

with throttle grip at stop, loosen this clamp, slide the rod on the cam follower side up untl the roller touches the cam ( on the armeture plate), tighten the clamp.


this is part of the link and sink also.... but it sounds like when you replaced the carb after cleaning it you just joined the two rods together without mating the cam roller to the cam.
the way this carb is made, when you disconnect that clamp, the cam roller flops over-away from the cam

 

[perkdp]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

did you get your problem solved ? what was it ?

 

[outlaw241]

Re: Got The Backfiring Solved, But New *problem Now!* Need Some Professional Help Aga

just a thought,it has to be in gear to advance the throttle all the way open