Tommy in FLL
Seaman Apprentice
- Joined
- Apr 10, 2009
- Messages
- 44
1996 Yamaha C85 powerhead. It has GOOD compression [all cylinders around 95 psi], and it ran perfect before I replaced it.
Replaced it?
Yes I did. Here's the problem: It was mounted on a 1996 Larson All American 16 foot bowrider, and if I brought it to full throttle for more than about 30 seconds, the overheat siren would sound. When I bought the boat and motor four years ago [I think I posted threads on here about this-], I thought either the temp sensor was bad or the head gasket was blown; I tested the temp sensor in a pan on the stove with a thermometer and it is working correctly. The thermostat was replaced, twice. It pees water like me when I'm drunk [sorry...], and I replaced the head gasket myself. A neighbor who has done this before assisted. Get this- All the bolts came out without breaking!
Still, it overheated. When we had the head off we could see the problem: The jackets were full of "goop". This motor is used in brackish water in Fort Lauderdale, and the owners NEVER flushed after running in the half-salt canal.
Goop: Semi clear, and obviously biological, thick, and with some sort of white paste mixed in. When we had the head off, we tried to scoop as much of this crap out of the engine as possible, but all we did was change the time that the overheat siren came on. This motor is apparently crudded up. The water jackets on this motor appear to be about 5 millimeters wide!
After interviewing several shops, I was advised that cleaning this stuff out of the block would be expensive. Instead of spending this money to make an old powerhead with considerable time work, I did some research and in October 2012 I was able to buy a NEW old stock zero-hour factory powerhead. The cost of this was sufficiently cheap for me to decide to buy if off of eBay and mount it on my engine. It runs like a top, just had it out.
Questions:
1. What is the old powerhead worth? It has good compression and is clean.
2. How do I break in the new motor? I was told no more than low cruise for 8 hours, and to not stay at any RPM for any long length of time.
3. I don't have a Hobbs meter, but when can I stop using 50% more oil in the gas than usual, which is also what my local shop advised.
Thoughts?
Thanx!
Replaced it?
Yes I did. Here's the problem: It was mounted on a 1996 Larson All American 16 foot bowrider, and if I brought it to full throttle for more than about 30 seconds, the overheat siren would sound. When I bought the boat and motor four years ago [I think I posted threads on here about this-], I thought either the temp sensor was bad or the head gasket was blown; I tested the temp sensor in a pan on the stove with a thermometer and it is working correctly. The thermostat was replaced, twice. It pees water like me when I'm drunk [sorry...], and I replaced the head gasket myself. A neighbor who has done this before assisted. Get this- All the bolts came out without breaking!
Still, it overheated. When we had the head off we could see the problem: The jackets were full of "goop". This motor is used in brackish water in Fort Lauderdale, and the owners NEVER flushed after running in the half-salt canal.
Goop: Semi clear, and obviously biological, thick, and with some sort of white paste mixed in. When we had the head off, we tried to scoop as much of this crap out of the engine as possible, but all we did was change the time that the overheat siren came on. This motor is apparently crudded up. The water jackets on this motor appear to be about 5 millimeters wide!
After interviewing several shops, I was advised that cleaning this stuff out of the block would be expensive. Instead of spending this money to make an old powerhead with considerable time work, I did some research and in October 2012 I was able to buy a NEW old stock zero-hour factory powerhead. The cost of this was sufficiently cheap for me to decide to buy if off of eBay and mount it on my engine. It runs like a top, just had it out.
Questions:
1. What is the old powerhead worth? It has good compression and is clean.
2. How do I break in the new motor? I was told no more than low cruise for 8 hours, and to not stay at any RPM for any long length of time.
3. I don't have a Hobbs meter, but when can I stop using 50% more oil in the gas than usual, which is also what my local shop advised.
Thoughts?
Thanx!