2007 Bayliner with 4.3L Mercruiser

Joined
Aug 4, 2017
Messages
12
Sorry if this has been covered before however I need some assistance.

15 and 20 amp fuses blew a few weeks back. Replaced 15 amp to get engine started again. 20 amp fuse constantly blows. Replaced diode with a new one. Boat started up fine. About 5-10 min later boat shut off. Both fuses blew. Replaced fuses. Tried again, 15 amp fuse blew after engine cranks for about a second. Replaced, tried again, same thing. Disconnected TKS module, tried again, same thing. Disconnected diode and boat runs. However, TKS module will not close. Did some looking around, didn't find anything out of the ordinary. Put back old diode and replaced both fuses. Boat starts but TKS will not close. With the new diode, TKS module would get hot on back in order for it to close. Old one, feel nothing. I am at a loss here. I tried to post pictures of a couple things but it says they are too large. Could my temp switch be bad? I downloaded the TKS manual and looked at the wiring diagram. On the engine I found on the top right side a connector with a yellow and black wire, the diagram says this is the oil pressure switch. On the other side is a 90 degree connector of some sort with only one wire running to it. I cannot seem to find the temperature switch on the engine. Do I just need to replace the TKS and go from there? What else can I do. Please help this is frustrating the crap out of me!!!!
 
Joined
Aug 4, 2017
Messages
12
Sorry if this has been covered before however I need some assistance.

15 and 20 amp fuses blew a few weeks back. Replaced 15 amp to get engine started again. 20 amp fuse constantly blows. Replaced diode with a new one. Boat started up fine. About 5-10 min later boat shut off. Both fuses blew. Replaced fuses. Tried again, 15 amp fuse blew after engine cranks for about a second. Replaced, tried again, same thing. Disconnected TKS module, tried again, same thing. Disconnected diode and boat runs. However, TKS module will not close. Did some looking around, didn't find anything out of the ordinary. Put back old diode and replaced both fuses. Boat starts but TKS will not close. With the new diode, TKS module would get hot on back in order for it to close. Old one, feel nothing. I am at a loss here. I tried to post pictures of a couple things but it says they are too large. Could my temp switch be bad? I downloaded the TKS manual and looked at the wiring diagram. On the engine I found on the top right side a connector with a yellow and black wire, the diagram says this is the oil pressure switch. On the other side is a 90 degree connector of some sort with only one wire running to it. I cannot seem to find the temperature switch on the engine. Do I just need to replace the TKS and go from there? What else can I do. Please help this is frustrating the crap out of me!!!!
 
Joined
Aug 4, 2017
Messages
12
I have downloaded service manual #41. This has a date of December 2004. Is there a newer manual for a 2007 model?
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
Beast - Please don't start more than one thread on the same topic. Both threads are merged.
 
Joined
Aug 4, 2017
Messages
12
Sorry for the double post.

So today I am out at the boat taking some readings. I am pretty sure my diode is fried. I only get about 3 ohms in each direction. I found that at what I think is the temp switch, unplugged I read 12+ volts. However when I plug it in and check the voltage at the tks connection I get only 3 volts. If I unhook the possible temp switch connection then the voltage at the tks connection reads 12+ volts. Is my temp switch not allowing the voltage to get to the tks so it can close? Unless because my diode is no good causing this. However when I put a new diode in yesterday it ran fine for a few minutes then both the 15 amp and 20 amp fuses blew. It didn't not blow the fuses until I put the old diode back in. I tried posting pics but can't seem to get it to work.

The 15 amp fuse that blew was the one on the back of the engine.

Any suggestions?
 
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