Hot (or warm?) Chrysler 105 or "So I bought this cheap boat..."

Possumworks

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So I bought this boat last year and, knowing zilch about outboards, failed to recognize that the engine was pretty much junk. The fact that my fellow Craigslister was less than honest didn't help my plight. I spent the summer overhauling the engine and only got it into the lake once last year before it closed. It ran perfectly and I followed the Seloc break in procedure running at between 3-4k rpm for about an hour. Additionally I ran very briefly above 4k and at WOT very shortly just to check function. I winterized the boat running non ethanol gas thru it and draining the carbs..

Yesterday I got it out again and continued below 4k rpm for another hour, and all was well. As soon as I increased above 4k the overheat horn went off so I idled down and the horn shut off after about 15 sec. I took the cover off and could briefly put my hand on the cylinder head without burning it so I continued on. We always had a good stream of water coming out the back, even with the horn going off. Additionally i was showing decent water pressure on the gauge i installed (pressure taken at the top of the thermostat housing.) Long story short, it got to where it would sound the horn after a couple of minutes above 3k rpm, so we limped back to the dock. Steady water pressure all the way home.

Got it home and checked the overheat switch in hot water (of course after snapping it off the block...) It closes at 200 deg. I've also red about "red" and "white" over temp switches. Mine appears white, but 200 is too hot...right?

Thermostat in hot water begins to open at 140
Compressions all 120 cold

I'm running 25:1 on the gas mix as recommended for the break in. Could this be making me too lean?

The engine was bored, honed, new pistons and rings installed
New water pump and housing, new thermostat, carbs cleaned and set up according to Frank's tutorial.
Timing set at 30 static also per Frank's info except that I used a multi meter instead of watching the spark
I'm running an MSD ignition with 2 coils as has been detailed in other places (which is fantastic by the way......well unless that's the problem I guess....) along with BUHW plugs

I've run it in a bucket and with the muffs at 12-1500 rpm and the cylinder heads are about 100 degrees checked with a no contact thermometer. Steady water coming out the back and out the little hole n the side of the lower end. It's pumping enough water that I had to keep the hose running pretty good to keep the bucket full.

Sorry for the long post just wanted to try and give you guys as much info as I can. Any ideas??
 

Possumworks

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Re: Hot (or warm?) Chrysler 105 or "So I bought this cheap boat..."

In case anyone is interested I added 1/2 tank of fuel at 50:1 and backed the timing off to 28 and the problem has gone away. Not sure which one was the solution, but I'm making 5k rpm at wot so I suspect the timing is not too slow. The TDC index appears to be accurate, but its hard to tell since there is about 2 degrees of no travel when the piston is at the top of the stroke.
 

foodfisher

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Feb 18, 2009
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Re: Hot (or warm?) Chrysler 105 or "So I bought this cheap boat..."

Just checked my book, 180* is ideal. Don't know how the change in fuel/oil ratio could affect that.
 

Possumworks

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Re: Hot (or warm?) Chrysler 105 or "So I bought this cheap boat..."

Just checked my book, 180* is ideal. Don't know how the change in fuel/oil ratio could affect that.

Thanks for the info! I read that someone had a similar issue on an Internet post elsewhere and didn't put too much faith in it, but it's really the only thing I've changed except changing he timing a couple of degrees. I wondered if I had the TDC index off a little (it was loose when I got the boat) so I went back and checked it with a dial indicator on #1, and it's accurate with a degree or 2. I've had it out twice with no overheating issues. Only other thing I can figure is that the rings on #2, which is closest to the overheat switch, chose to seat at when I happened to put the new fuel in...gonna run it again next week, I'll post again if it recurs.
 

foodfisher

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Feb 18, 2009
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Re: Hot (or warm?) Chrysler 105 or "So I bought this cheap boat..."

Off the subject but an earlier post had one degree off meant the difference between starting and not.
 
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