multiple cooling questions

[countryguy1717]

1997 Mercruiser 350 Magnum Ski (Carb). Serial number 0K040853

So last weekend the boat was running up to 200. This week I changed the impeller and thermostat. (160 kit). But now I have new issues

1. The thermostat kit has extra gaskets. Did I miss something? I pulled the old stuff out of the housing. Cleaned it. Put a cork like ring gasket into the housing, followed by the new thermostat, followed by the plastic sleeve, then put the gasket with the brass rivets on between the housing and manifold.. but I'm wondering what these are for? Especially the rubber ring. Was that supposed to go with the cork gasket?
Could it be a faulty thermostat?

2. I let it idle for a while and gave it some gas to about 2k. And my temp slowly rose to about 180, then spiked to 140, all the way down, would come back up to 160. It seemed really erratic. When I pressed on the hoses I felt water flow through all of them except for this one

3. I noticed a small amount of steam or smoke that seemed to be coming from these two hoses that run into the valve covers, I'm guessing a vent. Is that a problem?

4. There is a small drip on my raw water pump, I feel like I torqued them down pretty tight when I changed the impeller, and I used the gaskets. Would a small drip, maybe 1 drip per 1-2 seconds cause an issue?

I'm just trying to figure this out because I'm worried about taking it out tomorrow.

 

[BrianNJ]

Re: multiple cooling questions

1). The thermostat is probably designed for multiple applications and comes wit gaskets for each. No problem if you have no leaks.
2) Were you getting good water flow through the system? I would go out and keep an eye on it.
3) a small amount of vapor from the crank ventilation is normal. Excessive vapor while running might indicate blow-by due to bad rings.
4) it looks like you have a belt driven pump. That leak could become larger when the boat is in the water since there will be pressure from outside the hull.. It could also leak while the engine is off, meaning the boat could eventually sink if left in the water with the leak.

If trailering, I would go ahead out and keep an eye on the temp and the leak. If you plan to leave the boat in the water, fix the leak first.

 

[achris]

Re: multiple cooling questions

I hope you don't mind, but I added a line to the top of your post... Particularly when asking for information about parts having the serial number right there makes it easy for us to just pick it up and plug it into the Merc EPC, and get the parts exploded drawings...I like to see that information right at the top of every thread (but that's just me ), no missing it or having to ask for it again...

Ok, that out of the way....

1. Often parts 'kits' include parts for many applications, not just your particular engine, so having a few parts left over is not unusual... And from what I can see of the exploded drawings (the ones I'm looking at using your serial number ) you have done it right....

2. That sounds like the thermostat opening and closing. It's likely to even out once you have a load on the engine and more heat running into the new water entering the engine. The thermostat should not slam shut again because the new water hitting it is already quite warm.

3. Crankcase vents, yes. A small amount of vapour is not unusual... If it's steam, have you had 'moist' weather? Has there been condensation on the inside of the engine cover?

4. ANY drips need to be fixed! I would be checking that pump again.

From memory you used Sierra kits... My personal preference is OEM. Far less problems and inconsistencies... Yes they are a bit more $pendy, but I believe, in most cases (Manifolds, elbows, impellers and gaskets, eblows and shift cables), they are more cost-effective in the long-term...

Chris....

 

[countryguy1717]

Re: multiple cooling questions

1). The thermostat is probably designed for multiple applications and comes wit gaskets for each. No problem if you have no leaks.
2) Were you getting good water flow through the system? I would go out and keep an eye on it.

3) a small amount of vapor from the crank ventilation is normal. Excessive vapor while running might indicate blow-by due to bad rings.
4) it looks like you have a belt driven pump. That leak could become larger when the boat is in the water since there will be pressure from outside the hull.. It could also leak while the engine is off, meaning the boat could eventually sink if left in the water with the leak.

If trailering, I would go ahead out and keep an eye on the temp and the leak. If you plan to leave the boat in the water, fix the leak first.

I hope you don't mind, but I added a line to the top of your post... Particularly when asking for information about parts having the serial number right there makes it easy for us to just pick it up and plug it into the Merc EPC, and get the parts exploded drawings...I like to see that information right at the top of every thread (but that's just me ), no missing it or having to ask for it again...

Ok, that out of the way....

1. Often parts 'kits' include parts for many applications, not just your particular engine, so having a few parts left over is not unusual... And from what I can see of the exploded drawings (the ones I'm looking at using your serial number ) you have done it right....

2. That sounds like the thermostat opening and closing. It's likely to even out once you have a load on the engine and more heat running into the new water entering the engine. The thermostat should not slam shut again because the new water hitting it is already quite warm.

3. Crankcase vents, yes. A small amount of vapour is not unusual... If it's steam, have you had 'moist' weather? Has there been condensation on the inside of the engine cover?

4. ANY drips need to be fixed! I would be checking that pump again.

From memory you used Sierra kits... My personal preference is OEM. Far less problems and inconsistencies... Yes they are a bit more $pendy, but I believe, in most cases (Manifolds, elbows, impellers and gaskets, eblows and shift cables), they are more cost-effective in the long-term...

Chris....

Brian, i never checked before but im wondering why I dont feel water running in that hose. I never have the boat in the water more than 8 hours. Def not overnight, but ill check it again.

Chris, you don't have my serial number memorized by now? Haha jk.
So you think it might correct itself under load for a while? The thermostat is actually from napa. its not a sierra, but the impeller kit is.
there might have been a little condensation, it rained last night and my drain plug was out (right under the engine)

I'll try torqing the bolts again, also the two hoses on the back of the pump. I jumped the gun at first once i got it all back together i started it without tightening the clamps on the two hoses behind the pump until i saw it spitting water.

 

[achris]

Re: multiple cooling questions

...Chris, you don't have my serial number memorized by now? Haha jk.

I have the serial number of every engine I have ever helped with memorised... I'm just putting it up there to help other people...

...I'll try torqing the bolts again, also the two hoses on the back of the pump. I jumped the gun at first once i got it all back together i started it without tightening the clamps on the two hoses behind the pump until i saw it spitting water.

Yep, that'll do it every time....

Chris......

 

[countryguy1717]

Re: multiple cooling questions

So after a long sat afternoon, i went to change the oil, got an electric oil dipstick pump for $25 worked great, replaced with penzoil 20w50, quicksilver filter. Went to re torque the water pump and noticed it had hairline cracks around the rear cover. Luckily a shop was open 30 miles away and had the part. Jumped on the bike, headed over and bought a replacement one piece, its plastic with just a rubber o ring but it works... Put another new impeller in. Hooked it up. Thanks again for everyone's help. I was able to get out on the river that afternoon to take out my fiances mom and her friend. The boat ran good, the temps did get up to 190 after cruising a while a few times but it would drop back down to 180. Do you think that's too high?
New water pump.

Now here is my newest issue i found. The water pump pulley has a chip on the outside?... It didnt cut the drive belt apart but obviously I want to get it fixed.

Any input on how to replace that part? Does the replacement come with the shaft that runs into the impeller? Just get a replacement and swap it out? Is the part number or size of the belt on the parts catalog? Any ideas about the semi high temps?

Btw Chris, you were right again. After putting load on it the temp gauge was working. It wasn't so erratic. It would sometimes hit 190 and slowly drop to 180-170 but not near as bad as it was on the fake a lake.

 

[countryguy1717]

Re: multiple cooling questions

I have the serial number of every engine I have ever helped with memorised... I'm just putting it up there to help other people...



Yep, that'll do it every time....

Chris......

I see 807731 for the pulley. Im assuming it just connects by number 23 and 25 nut and lock washer on the parts diagram?

 

[BrianNJ]

Re: multiple cooling questions

The pulley is pressed on. Yours is a little different from mine, but I think this is the econo version of the tool you need. Pulley Remover and Installer Set

A new pump generally does not come with a new pulley. I used this tool to swap my pulley to a replacement pump. It is a bit of a pain to use. There are better versions available.

 

[countryguy1717]

Re: multiple cooling questions

I wonder if I can rent something like this at oreillys

 

[NHGuy]

Re: multiple cooling questions

A lot of the auto parts chains will sell those & allow return. So it's a kind of a loaner tool. If you do that open the box right away at the store to make sure everything you pay for is in there.
BTW you have to use a puller, you can't rig up something from your tool box.

 

[Speakrdude]

Re: multiple cooling questions

That sounds like a challenge, right there.....