Engine noise after putting in forward at full throttle. NOW WHAT?

la1exotic

Recruit
Joined
Jun 2, 2019
Messages
1
We went to the lake the other day. I backed the boat in the water put it in reverse after starting it and once in the water accidentally hit the throttle to full panicked and put it immediately in drive then I heard big noise coming from the engine and then the boat had no more power it almost felt like it was running on one cylinder. Once I got home I checked both cylinders for compression I had 120 psi on both I checked the lower unit impeller it was in good shape all the gears were engaging forward and reverse no problem no broken teeth the side of the pistons look good I could see them after removing the side plates and when I remove the spark plugs while running the engine one at a time it seem to affect the engine which tells me both of them are firing ok. Now when I turn on the engine and it’s idling it doesn’t sound right and At full throttle is even worse it seems to be stuttering bogging down and there’s almost a mechanical sound coming from inside of the engine which I’m not sure what it is but I can’t help but feel like something is broken. I don’t know what to do as I’ve done everything I think I can to check do you have any suggestions? The engine is in 1967 Evinrude lark 40 hp I would like to keep it if I can fix it but I’m trying not to spend a fortune to do so.
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
That would be a Selectric Shift motor. You say it still shifts ok, so let's hope there is nothing broken in the lower unit. So, I suppose a good move would be remove the lower unit and see if the noise is still there. I hesitated saying that because running the motor any more could cause more damage. But you say you've already run it at full throttle with the noise present. If it is broken inside, that certainly would have finished it off. Good luck.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,990
I thought the Evinrude control box prevented the shift buttons from being pushed at speeds higher than fast idle?

I find it hard to believe the internals(Shift spring/coils) of the gearcase are not broken.

The sound you heard when the incident occurred, can you describe it?
Also you say it is making now as you run it, description
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
That is true about the push buttons. Unless somebody has tampered with or removed the white sliding interlock.
 
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