25 horse shutting down

[cary king]

I have a mariner 25 hp motor serial number 695s-15335 year model unknown. The problem is that when the engine gets up to operating temps it wants to bog down and the plugs load up on fuel and it dies. If i remove the plugs, blow them out and let the motor sit for twenty or so minutes it will start right back up until it gets warm and the whole process starts again. I have checked the entire fuel system and there seem to be no problems. I was told by a local shop that it was possibly the cdi ignition module and something called an exciter coil. Would either or both of these parts cause the engine to shut down when it gets warm? It is a manual everything motor (i.e. tiller handle, manual choke, pull start)

 

[rodbolt]

Re: 25 horse shutting down

could, they are pricey so I would test them as per the service manual before replacing them, a bad fuel pump can create that issue as can an engine thats overheating. what kind of electrical test equipment do you have and do you have the service manual?

 

[rocker3]

Re: 25 horse shutting down

I have a similar problem with a 25 hp yamaha,oil injection. Runs great until it warms up,then bogs down. Let it sit for awhil and off you go until it warms up.Have been times when I would keep running it as it was boging down and it would kick back in and run good for awhil.Heres what I have done and it still does it. Got new cdi($280.)new coils ($80.apiece)Had carbs rebuild,new fuel pump.Compression check ok. Not overheating. Been told that it may be a blowed head gasket or cracked head. That when it warms up it loses compression. What is and where is the exciter coil? Is it in the magneto? Any ideas? Thanks