Would also test the thermostat housing with an IR gun to see if gauge is off.
If you take the thermostat out you can test it in a pot of water use a meat thermometer to see what temp it starts opening at
Less work than you think as long as there is 4" in front of the 4.3
if you friend has a complete merc pulleys to prop and boat is in good shape this is the way to go. Otherwise yes a 4.3 out of a wrecking yard is cheapest way
I edited the post and added it , I think your first response was while I was editing…
10 psi per 1000 rpm hot is fine. Check for backlash in timing . If I recall 3.0 s can be a little clacky or at least mine was. I think on the trailer and running on muffs it was louder than my current 5.0
You can probably diagnose the timing gears with out removing the cover. Take the plugs out turn the crank and see if there is excessive backlash making the cam, distributor shaft , or valve train move when you reverse crank direction. May have to pull lifter side cover to see cam
what oil...
When it happens check to see what spark strength is with gap tester , see if you have proper volts to positive side of coil ( not sure if u have points or electronic) , disconnect tach wire at coil
if you ever have an issue out on the water you will not need the manual ...
I keep a spare module, trigger sensor and coil in my tool box on the boat...
I meant 16" pitch I generally ignore the diameter. You mentioned 16" being too low, 21 " pitch being a little lazy. was wondering if you had tried a 18" or 19" pitch being in between. I had found the 18" vortex good for all around , would just swap it for the 16" when skiing.
Thats nice always help folks, I figure it could be dead in the water next time. 4 years ago saw a boat in middle of lake with engine hatch up, stopped by. there engine just quit locked up... Towed them about 2 miles to the nearest launch
Very similar to my old boat that had a 3.0 could make it work but need more azz...
my experience with the 16 was not quite as high revs but u there. Did you try a 18" or 19" 4 blade ?
In the end bigger boat and engine is probably in your future. We went from a 17 or 18ft 3.0 to 21 ft 5.0 ...
this is out of a merc 5.0/5.7 engine manual specs are same for both the EST coil and TB coil...
Primary side - .6-.8 oms
Secondary - 9,400-11,700 ohms
Attached is a snip of how to test the pick up coil in the est . This is for a delco but Ass/u/me yours is similar
if you had issues on the trailer with the delco yes the module or trigger sensor in there is messed up. It takes absolutely no power to rev the engine up on the wagon with no load.
Have you used a spark gap tester on both. Willing to bet the delco is not putting out any spark strength. I...
That is a good plan. Maybe not at 22 degrees if initial is too low but say 25-26. That should give a good indication of if the issue is due to total timing or spark strength/quality. Even if idle quality suffers once you get into the throttle it will start advancing.
On the timing difference -...
