'97 Evinrude 25hp throttle issue

[jakedaawg]

T It does not even increase the RPMs so even if the motor was overworked I would still get increased RPMs but limited acceleration .

Absolutely not true

 

[ondarvr]

Normally the RPMs will change even idling when you pull a wire off, but it will make a much bigger different on the water.

 

[racerone]

That is a recirculation tube.-----Does not interfere with operation of reed valves !--------Motor speed has to change when you pull off a plug wire.----Something is wrong here.-----Flyweel key checked ??

 

[WhiteRice]

Flywheel key has not been checked. Does the flywheel itself have to be removed to simply check to see if the key is sheared?

 

[WhiteRice]

If I did indeed habe a sheared flywheel key, wouldn't that keep that flywheel from turning? Or is the issue when the motor is put under load, the flywheel will not turn if there is a sheared key? I know in my dealing with small motors (mowers, etc.) I would be in a "no start" situation with a damaged key

 

[jbuote]

No, the flywheel key lines up the flywheel on the crankshaft.. It's the taper and the torque on the flywheel nut that holds it in place, but if the key sheared, the flywheel could shift on the crank throwing the timing off, so it wouldn't run right, or at all depending on how far off it slipped..

​That's the BARE basics of it, but Yes, Use the proper puller and pull the flywheel off to check the key.

​Jakedaawg, ondarvr and racerone are all excellent.. Between them, they won't steer you wrong!

For what it's worth..

 

[WhiteRice]

From what I've read... it's all solid advice and I appreciate all of it. I just want to fish...lol

 

[racerone]

Yes I know how to repair Briggs @ Stratton points engines too.---But this is a motor with electromic ignition.---A sheared key throws out the timing !---It wll still have the exact same spark just not at the correct time !

 

[WhiteRice]

No Title

So I did some additional searching about checking flywheel position without removing the flywheel. If I read this right, if I move the flywheel manually until Cyl #1 is at the top of it's stroke, my flywheel should be where my motor states is it's BTC. In my case that would be 20. In the first pic I had to mark 20 in yellow (where my pointer was) because I had to remove the pointer to get the intake manifold off to get a get view of the rod. Pic 2 is the piston in its highest position. It's reeeeeally close to 20 so if I am doing this and reading correctly, my flywheel "should" be in its correct position, right?

 

[jbuote]

Actually, No....

​If you put #1 cylinder at the TOP of it's stroke, then the flywheel should be showing TDC (Top Dead Center), that is 0 degrees...
​So, with #1 piston at the top of it's stroke (highest positon) you should be at 0 degrees or TDC....

​If at the highest point of the piston (#1) you're seeing 20 degrees BTC, then I'd take that as a clue the key might be sheared actually..

When I did that test on mine, #1 at highest point had TDC exactly 180 degrees off..
When #2 was at it's highest point, I showed 0 degrees.. (TDC..)

​It was enough that I had to ask here which cylinder was #1..
​Of course, it's the top cylinder.. So.. I had a sheared flywheel key..

​Even though you're seeing 20, and that matches a figure you have for timing, that is NOT correct when #1 cylinder is at the top of it's stroke..

​At this point, Pull the flywheel.. I'm really betting the key is sheared..
Sorry..

 

[WhiteRice]

Gotcha... I actually did that late last night and was hopeful about the flywheel position yet frustrated that I was still running into a dead end. I don't have the means to pull it (the two closest AutoZones to me do not have a flywheel puller to loan) and I don't want to attempt pulling it without one. I may end up having to take this into the shop :-/

Thanks for the info jboute

 

[ondarvr]

A puller at Harbor Freight will cost a few bucks, the shop probably has a minimum fee of maybe $100.00, and at this time of year a several week wait. You might get lucky though.

 

[jakedaawg]

Just outnof curiosity, did you set the pointer?

There are steps in volved in zeroing the pointer so that it really reads tdc.

While it would not be rare for a flywheel to read 20btdc usually you find them much further out.

 

[WhiteRice]

The pointer is only adjustable by 1-3 degrees left or right only. The pointer bracket is actually held in place by the intake manifold so there really isn't anywhere else for it to go. In my pic of the flywheel, the small bored-out hole is where the pointer screw threads through.

 

[Newyota]

I got a harmonic balancer puller from advance auto for my 9.9hp.Had to supply other bolts though.Never pulled a larger fly wheel with it.

 

[jbuote]

^^^ I too got a harmonic balancer puller from an auto parts store... Definitely had to get different bolts to use in the three flywheel bolt holes on my 50hp as the bolts that come with it weren't correct, but the harmonic balancer puller with correct bolts worked for me anyway..
Something similar to this:

 

[WhiteRice]

No Title

Got the balancer puller and yanked off the flywheel. Thanks for those that made that recommendation. Flywheel key did not appear to be sheared. Found a key (bought 2) from a local shop that was a Johnson part # match. The key was slightly unseated (pushed in further at the bottom for some reason) so I removed it, inspected it and re-installed it. The flywheel did not have any significant scoring inside of the hub. I couldnt see exactly where the key was due to the location of the nut. I guess back to square 156... Thanks for the input though guys. I really appreciate it. I guess now I am narrowing down to a fuel system issue of some sort. I dont know :-/

 

[WhiteRice]

Gentlemen... Any other ideas? About to start tearing into the fuel system (pre carb) and see what I come up with. Not sure what I am going to find because the three times I have removed the carbs, there seems to be enough fuel in the bowls. Fuel filter is easy to blow through and the lines do not appear to be in poor condition (although I just bought 6ft of 5/16" and 1/4" fuel line).

***Update to flywheel though***
After re-assembling everything, the pointer is now at "T" with cylinder #1 at top. I was at 20 prior to removing the flywheel but I could not see the position on the key prior to removal since the nut was in the way when the flywheel popped up.

 

[jbuote]

Well, Not sure why it's different, but you have a different result after pulling and re-installing flywheel....
​As long as the tapers were clean and dry, and torqued back on properly, I'd consider running it and testing a bit..
​Unless you feel you have reason to, I wouldn't try to "Fix" anything else until the new flywheel result is tested..
​It's now different.. so run it and see..
One thing at a time...

​But, again, not an expert.. Just my thoughts.. LOL

 

[WhiteRice]

True jboute.. I can't get it out again for another 2 weeks but I will just have to wait