351 overheating

I wish gravity were the answer, but we were sitting in the creek trying to take the strainer lid off to re-seat the o-ring, but the water was too hot. Again though, the plumbing is correct and the RWP pulls strong from the bucket. It also pushes it out of the exhaust, but maybe not as efficiently as Jim's GT40 clip. I think the circ pump is working, but at partial capacity. It is the original pump and has slight wobble to it. I've ordered the circ pump for a Saturday replace.

Aren't carbed boats running 140 and efi 163? Do you have the correct thermostat? Looks like a sender or gauge. Good luck

After troubleshooting the Teleflex guide, here is what I found:

Codes on side of the the temp sender- one side = 02020, the other side = 782. Neither of these are listed in the manual. Is the temp sensor specific to the temp gauge?

At the temp sensor I am getting about 620 ohms. This falls into the lower acceptable range of 600 to 800 ohms.

Between the I and G terminal on temp gauge, I am getting 10.1 V. Again the lower of the acceptable range of 10-16 VDC.

When I move the S wire to the G terminal, the Teleflex troubleshooting guide says this should peg the temp needle to 240 and it does not move the needle position. I am correct to assume then that the gauge is the issue?

I connected a ground to my fuse black installed for the stereo system and that had the same result with not spiking the needle to 240+. Also the engine was not running when I took the readings I gave earlier that may explain why they were low.

That's a little bit of a toughie.

At least two issues, one being the gauge/sender situation, and one (or more) making up the actual cooling situation.

Did you figure out if the engine actually did overheat? I guess it would be very coincidental for both hoses to randomly split.

You need to start with the bucket test, google correctcraftfan bucket test. The essence of the idea is that you make the boat pull it's own water from a bucket, rather than force feeding it with a hose, to get an idea of what's going on.

Okay, thanks for the help. The 'bucket test' materials helped me diagnose the problem. I'll explain what the problem was (it was a popped freeze plug) and then ask for more help (I can't figure out how to fix the freeze plug.)

When I got all the hoses and exhausts and everything back in place, I started the bucket test, and immediately noted water pouring out of the side of the block on the starboard side.    It was a freeze plug.   When I winterized, I pulled the lower parts of the hoses and drained it, and then pulled the upper parts of the hoses and poured in about a gallon of RV antifreeze. In retrospect, I should have used more antifreeze, and/or run the engine a bit to make sure it mixed thoroughly around the block.   There must have been a pocket of water in the lower part of the engine. It was a particularly cold winter this year in NC; I'm sure my winterizing would have not been up to scratch for colder areas. The missing freeze plug must have (1) caused the engine to overheat, stressing the elderly exhaust hoses and blowing them, and (2) left no water to flow over the engine temp sensor, accounting for the very low temperature reading.

Now, my question is, what do I do about it?   The videos I've seen online about how to hammer the plugs back into place presume you can swing a hammer onto the plugs to pound them in, and these plugs are blocked thoroughly by the engine mounts. I can press the plug in with my fingers pretty easily, but that seems inadequate to make them stay, even using gasket shellac as suggested. It might be that pulling the engine and unbolting the manifolds would give me some leverage, but that's too horrible to even think about.

Any advice? Oh, it's a '79 Mustang with a 302 Ford V8, if that helps.

-Boyce

Finally found the issue! I have been so focused on getting cold water into the engine that I overlooked the hot water getting out. The exhaust manifold riser was swollen so bad from corrosion that it was letting a small portion of hot water out of the engine. Two photos, 1 is the old riser and 2. the new riser. Replaced both risers, dunked her in the creek for a test run and she is running like a top!

I managed to get it fixed, so I thought I would add a note or two.   First, I never did the standard plugs in; I use the "performance" ones you can get with a nut in the middle of it that tightens. That was way easier than pounding the brass one covered in gasket seal in. I just never got the knack of getting it in there, even using the trick with freezing it.

Secondly, taking ONE engine mount is not a big deal, just some wrench work.   The remaining three support it fine.

The biggest problem was that the clearance between the engine mount and the freeze plug was still really low.   My experience was that with the freeze plug mounted and tightened, the engine mount would fit, by about 3/8".   So what I ended up doing was putting the plug in, remounting the engine bracket, THEN tightening the nut on the freeze plug. The bolt then comes out enough to press tight against the engine mount. It's hardly "factory", but it works and stays in fine with no leakage.