Engine temp questions and steam out exhaust

I recently replaced my impeller, I’m running on the hose and getting some steam off the exhaust, not sure if that’s normal. I confirmed my thermostat is opening at 145 in some water on the stove. I have good water coming out the exhaust, my impeller is sucking up everything from the hose.

My heads are reading 175 with the IR gun (didn’t run it any longer when they hit 180). Is it possible the water pump is bad? (See photo below) the hose to the right of my hand was cool, when the heads were hot, is that normal because it’s the water intake hose?

I really want to water test but not sure it’s a good idea. Maybe the motor was hot because the thermostat just opened and it didn’t have time to come down before I shut it off.

https://drive.google.com/file/d/1_2osQWtH-JGOQSY1KHeghf3EODayIzjT/view?usp=drivesdk

Mpost wrote: I would give it a try in the lake on the trailer and see what you get. Some say you may not be getting enough water thru the hose depending on your hook up. I just checked my the other day In the lake and the hose from the RWP was running just a little higher than lake temp. Never checked the heads but the hose from the thermostat housing to the engine water pump was running a consistent 135-140, Sam as my gauge was reading. Never checked the heads but the lower part of the exhaust manifolds were also running at 140 also, until I shut it down. Then the EM started rising into the 160-170 range. Your impeller wasn't in pieces when you replaced it was it??

My impeller was in pieces. I took off every hose and flushed. Flushed and checked the trans cooler. Took off thermostat, fished pieces out of there to. Is that hose next to my hand supposed to be cool when running? Just want to make sure my water pump is good, not sure where else to check from here.

Thanks

KENO wrote: The water from the raw water pump goes to the thermostat housing and some goes to the exhaust manifolds and some to the hose you're asking about. It's the suction for the Engine Circulating Water Pump It'll be cool till the thermostat is open and some mixing takes place in the thermostat housing and eventually it will be a lot warmer due to the mixing, essentially the same temp as the engine Like Mpost said, the hose from the Raw Water Pump up to the thermostat housing will be the same temperature as the lake/river/hose

So I ran it on the trailer in the water for 10 mins, all my numbers checked out except that riser on top of exhaust manifold I saw 160 on the passenger side. Or is that normal? Drivers side was 130. Photo added to show the area.

https://drive.google.com/file/d/1CokV7olpG6jk35V817rThlzfvlYFjrRT/view?usp=drivesdk

Hollywood wrote: Ticking time bomb. You should sell it.

Haha hell no, I’m restoring this boat and will pull the motor some day to rebuild
Just don’t want to fry it this early. I know GM cars, restored a 72 camaro but the marine motors are all new to me

MrMcD wrote: I suspect you still have a couple pieces of that old impeller hiding in your system or both manifolds would be within 10 degrees of each other. On the garden hose I had lots of water running out my exhaust as soon as it started and when I revved it you would see water blow out 8 feet or so. When I installed the RWP inverted I had zero flow out the exhaust manifold. I know, I should not have done that!

I wonder where else to check. I pulled all hoses and flushed, pulled thermostat housing, flushed trans cooler and also the RWP housing. Any ideas on other places to check?

When I checked mine this week, the lower part of the manifolds was around 135-140 and the risers were a little cooler. Again that was in the lake and at idle. I also checked the hose and downpipes towards the muffler and they were about the same as the riser.
Did notice that the bottom of the fiberglass downpipes was cooler than the tops. Made sense at idle, since the water would mostly be running on the lower part of the tube. Both sides gave me the same readings.
I have heard of people finding chunks in the inlets to the manifolds. Maybe a shop vac would pull things out the inlet.?

Don't confuse him with fiberglass downpipes, he'll never find them, he has rubber hoses and maybe no mufflers at all.

Mav

Do you have mufflers? If you do a broken baffle lodged in the wrong place can affect your flow on that side of the engine.

Haven't you checked the manifold inlets already? it was mentioned earlier in this thread

Is all this checking taking place at idle speed?

Give it some speed to increase the water pump flow and check your readings.

Do you have the same temperature at the inlet to each manifold from the t stat?

Sometimes I'm about as sharp as a bowling ball, but if it was me I'd remove the thermostat, put some actual load on the engine (ie: take it for a ride) and check things out You'll have plenty of warning if things are getting hot.

A ride without a thermostat isn't gonna hurt anything.and may tell you a few things

Good luck, happy travels

Glad you found something.

I guess you found something else too

You could hook a temporary tank to the fuel pump like in the link below and determine if you have a problem upstream of the pump or from the pump to the carburetor. The tank needs to be vented.

If it runs good on the temporary tank, it's time to look at the suction line in the installed tank, the anti siphon valve and the fuel line between the tank and the fuel pump.

Also if you think it's fuel, look at the ignition system and vice versa. You'd be amazed at how many times that finds the problem

Crmaverick wrote: Thanks for the info I ordered a new HEI distributor. Wires, plugs and carb rebuild kit. Gong to start fresh and see where I end up

Hopefully you just left out a word between HEI and distributor like "marine"

Must be something making you think you need a whole new distributor?

Crmaverick wrote: KENO wrote: Crmaverick wrote: Thanks for the info I ordered a new HEI distributor. Wires, plugs and carb rebuild kit. Gong to start fresh and see where I end up Hopefully you just left out a word between HEI and distributor like "marine" Must be something making you think you need a whole new distributor? It was all corroded inside the cap. The tune up kit was only 100 cheaper, so I figure drop in a new distributor and set my timing

Something tells me you're avoiding the "marine" question

Crmaverick wrote: Lol was I supposed to order a special marine distributor? I got the standard AC Delco

Well......................sure

You showed up on CCF with questions about stuff, you should keep asking if you're not sure, or do some searching on the site.

One reason to get a marine distributor is that it's more expensive, so you can sink even more money into your boat

But the real reason is the spark arresting capability of the distributor as compared to the automotive version.

It keeps you and anybody else in the boat with you from being at "ground zero" in an explosion if gas vapor meets up with the spark in the distributor.

How about a few pictures of what's on the boat now? It looks like an HEI in one of your earlier pictures of the engine and it might be a marine unit

Does it have a vacuum advance canister( hint.......it shouldn't have one) on it or can you maybe see the brand of distributor on a tag or label or see anything that says "meets SAE J 1171 or meets USCG specs"?

Some people use automotive or "convert" their automotive, some better than others" but it's kinda' like rolling the dice.

So somebody stuck an automotive HEI on it sometime over the years

If you want to do it right, click on the link for an example of a marine HEI for your Chevy.

link

You can order it with a variety of different colored caps.

I figure it's a wee bit pricier than what you ordered

KENO wrote: Maybe to answer the next question before it gets asked, things that should be "marine" for that era boat/engine for purposes of minimizing an explosion would be Distributor Starter Alternator Fuel pump Carburetor Any rubber fuel line on the boat Flame arrestor on the carburetor Engine mounted starter solenoid (some older auto solenoids were vented, marine aren't) Automotive are sealed these days, so no real difference other than what the studs are made of. You'll notice that the list is things that make sparks or things that can leak gas. A search of each on CCF would get you lots of info on any of this stuff

Cool thanks for all the good info. I’m going to take your advise and get the marine distributor and return the one I bought. I did order the correct marine spark plugs and the Holley 800 carb decodes to the marine spec version to.

Don't take the chance on non marine parts.