Symptoms came up quickly

mbrasch

Cadet
Joined
Jul 20, 2010
Messages
12
I have a 93 mercruiser 4.3 Alpha Gen2 S#0D843639. This past weekend was my first time out this season. The boat ran excellent all day saturday. Was thinking it was going to be a good season. Went out Sunday for some more watersports on the same tank of gas. At first I noticed a slight pulse in the engine RPM at WOT once planed out. Made a note of it and continued. After a few runs, all of a sudden we couldnt even plane out anymore. I had to leave to come back home for the week so I didnt get a chance to look at anything. Looking for some ideas on where to start looking. Thanks
 

greg82255

Senior Chief Petty Officer
Joined
Oct 26, 2009
Messages
781
Re: Symptoms came up quickly

I have a 93 mercruiser 4.3 Alpha Gen2 S#0D843639. This past weekend was my first time out this season. The boat ran excellent all day saturday. Was thinking it was going to be a good season. Went out Sunday for some more watersports on the same tank of gas. At first I noticed a slight pulse in the engine RPM at WOT once planed out. Made a note of it and continued. After a few runs, all of a sudden we couldnt even plane out anymore. I had to leave to come back home for the week so I didnt get a chance to look at anything. Looking for some ideas on where to start looking. Thanks

I'd start by replacing the water separating fuel filter and pour the contents into a clear container and look for water. Sounds like you may have some water in your fuel. It could be a few other things but the filter is a quick easy thing to check.
 

mbrasch

Cadet
Joined
Jul 20, 2010
Messages
12
Re: Symptoms came up quickly

Good idea. I will check that out this weekend. Makes sense it could be that. If not that, any other ideas? I am only there on weekends, so I dont get much time to work on things. I'd like to have a few things to look at in case its not one or the other.
 

Failproof

Petty Officer 1st Class
Joined
Sep 26, 2011
Messages
273
Re: Symptoms came up quickly

Too many possibilities! From fuel to coil to engine spark controls to ????
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Re: Symptoms came up quickly

Good idea. I will check that out this weekend. Makes sense it could be that. If not that, any other ideas? I am only there on weekends, so I dont get much time to work on things. I'd like to have a few things to look at in case its not one or the other.

Ayuh,.... Welcome Aboard,.... How Handy are ya, 'n how big is the toolbox yer bringin',..??
 

mbrasch

Cadet
Joined
Jul 20, 2010
Messages
12
Re: Symptoms came up quickly

Ayuh,.... Welcome Aboard,.... How Handy are ya, 'n how big is the toolbox yer bringin',..??

I'm pretty good with a tool. Always ready to learn new things. I was hoping maybe my symtoms lead to something obvious.
 

mbrasch

Cadet
Joined
Jul 20, 2010
Messages
12
Re: Symptoms came up quickly

I'd start by replacing the water separating fuel filter and pour the contents into a clear container and look for water. Sounds like you may have some water in your fuel. It could be a few other things but the filter is a quick easy thing to check.

You were right on with this. I replaced it, and the engine ran great all weekend until the end of day Sunday. Toward the end of the day, I started getting a very loud squeel, like a belt squeel. I didnt have time to pinpoint it this weekend, but it was at idle to about 1200 RPM. Once I increased the RPM's it went away and stayed away until I shutdown and restarted. Then it usually came back. Next weekend I will need to start it up on land and try to figure where it is coming from. It seemed from a very quick listen to be coming from the alternator area. It did however at one point start to scream one time as i lowered the trim but that could have been a fluke. The noise was definately coming from inside the engine compartment. Any recommendations to look for are welcome. Thanks
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Re: Symptoms came up quickly

You were right on with this. I replaced it, and the engine ran great all weekend until the end of day Sunday. Toward the end of the day, I started getting a very loud squeel, like a belt squeel. I didnt have time to pinpoint it this weekend, but it was at idle to about 1200 RPM. Once I increased the RPM's it went away and stayed away until I shutdown and restarted. Then it usually came back. Next weekend I will need to start it up on land and try to figure where it is coming from. It seemed from a very quick listen to be coming from the alternator area. It did however at one point start to scream one time as i lowered the trim but that could have been a fluke. The noise was definately coming from inside the engine compartment. Any recommendations to look for are welcome. Thanks

Ayuh,.... The Belt is loose,... or the bearin's are bad,... Whenever ya use electricity, it squeals...
 

mbrasch

Cadet
Joined
Jul 20, 2010
Messages
12
Re: Symptoms came up quickly

Thanks for the reply Bondo. I will verify this weekend. If thats the case, how quickly will those bearings fail? Can I run another weekend like that? If I verify this weekend, I wont have a new alternator until the following weekend.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Re: Symptoms came up quickly

Thanks for the reply Bondo. I will verify this weekend. If thats the case, how quickly will those bearings fail? Can I run another weekend like that? If I verify this weekend, I wont have a new alternator until the following weekend.

Ayuh,... How am I supposed to know that,....

They're yer dice, roll 'em if ya want....
 
Top