Possible water pump issue?
 

Ok another problem with this engine... When I', running this on plane the temp will climb up to 190 degrees. If I come off plane to a fast idle (1500 rpms) the temp will fall back to 150. I pulled the hose off the t-stat housing and the water pulses out when running? Is this normal? The impeller looks fine and is less than a month old.

Sounds like that motor's had a tough life so far.. Overloaded, no fuel, overheating.. before you destroy a nice piece you may want to stop and get some stuff figured out. Do you have a water pressure gauge, oil temp, the ability to check AF ratio, someone who can read plugs and tell you if your timing and heat range are good, etc. Get all the little stuff figured out first and then go wind 'er up and see what kind of speed you can get. :drink: and yes at idle it will pulse a bit...

Its not as bad as it sounds, lol. I've bearly run the boat overloaded.. As soon as I see a prop is too steep, I pull the prop and replace with the old 21. The fuel issue is new. I'm going to tear down the carb this morning and see if there is junk in the jets. It still bogs at 4800 rpms so something is clogged somewhere. I have no way to test AF ratio.

In case anyone else is running a crossover and has this issue, drill 4 -1/8" holes in the thermostat and the problem will vanish!

I will assume you have the bravo, where did you drill the hole in the t-stat right on top? My BBC/alpha will run hot after a long run when I stop to idle it climbs to 190 temp at idle untill I give it a little gas back down to 150 temp.

Check your water hose were it attaches to the transom assembly.There is a seal/oring there that gets compressed more so if the boat has been run in salt.That is the feed line coming from the pickups in the drive.

And if this is clogged its possible that the impeller is now bad also as it may have not been able to pull in enough water.

+1,,this fixed my saltwater boat,,,you could have some seaweed restricting water flow thru the drive,,,had that problem on a fresh water boat,,,i hooked up the hose,,,turned on the water ,,,i could tell right away,,,that the flow going to the sea strainer was not right,,,

Sorry to be late in the game but what are you running again?
1. motor size, What t-stat
2. Ignition Timing, plugs , gap
3. carb size, jet size, power valve fuel line size
4. Drive plus ratio and prop
5. what is your wot rpm

1. These are what you need to keep your engine from failing
oil temp 220or less
2. exaust temp on #7 right @ the head port this will save you from a melt down and give you a safe exhaust temp from idle to wot 1200 f 1350 f
3. AFR meter is the best for tuning brands innnovate motor sports LM-2 or the fast unit

That is usually because the Alpha sea water pump is low volume at idle.
Steve