Overheating

[hopes&dreams83]

Everything was going great. About 5 hours on the engine and drive and I thing overheats on me. Shut it down right away don't think I caused major damage to the engine tho. So what the hell could this be. Everything is new except manifold and oil cooler for power steering. New water pump and impeller in the drive. So i popped off the new thermostat and its stuck. Just under 5 hours of operating and its shot. Awsome. So i try running with no thermostat. Still instantly over heating shut it down. So today I figure start from the water pick up vent and work back till indont see water. I popped off the water line that comes from the transom to the oil cooler and fired it up no water at all comes out bone dry. How could this be? Impeller and outdrive have just under 5 hours. I guess what I'm wondering is can a stuck thermostat causing overheating also burn up the impeller in the outdrive? I can't see how but I'm no expert. If not what could cause the impeller to burn up like that after less than 5 hours. Never ran it dry and the vents were the first thing I checked and didn't find any dibree obstructing it

 

[alldodge]

Need more info????????????
What motor ???
Is it a Alpha Gen 1 or 2, or even a Bravo????

With a oil cooler it's most likely a Bravo and maybe a BB

 

[Scott Danforth]

If not what could cause the impeller to burn up like that after less than 5 hours. Never ran it dry and the vents were the first thing I checked and didn't find any dibree obstructing it

5 hours calendar time or 5 hours on the hour meter?

Doesn't take much to starve an impeller. A big leaf, a plastic bag, run in muck

Mercruiser/Quicksilver impeller? Sierra impeller? Amazon special?

 

[hopes&dreams83]

5 hours calendar time or 5 hours on the hour meter?

Doesn't take much to starve an impeller. A big leaf, a plastic bag, run in muck

Mercruiser/Quicksilver impeller? Sierra impeller? Amazon special?

It came with the drive. Sei stern drives. Not calender or meter. I've just been recording run time on my own. I have a break on procedure I have to follow from the engine builder as well as sei sterndrives

 

[hopes&dreams83]

Need more info????????????
What motor ???
Is it a Alpha Gen 1 or 2, or even a Bravo????

With a oil cooler it's most likely a Bravo and maybe a BB

Sorry I guess I double posted and the one that got deleted had the info. It's a carburated 1999 5.0 mercruiser alpha1 gen 2.

 

[alldodge]

Sorry I guess I double posted and the one that got deleted had the info. It's a carburated 1999 5.0 mercruiser alpha1 gen 2.

No, it did not have the info, I deleted it and MOD's can still see it.

Pull the lower and check the impeller

 

[alldodge]

Retact, yes it did say "carburated 1999 5.0 mercruiser alpha1 gen 2."
but should not have had 2 post in same section

 

[Scott06]

It came with the drive. Sei stern drives. Not calender or meter. I've just been recording run time on my own. I have a break on procedure I have to follow from the engine builder as well as sei sterndrives

if its an sei drive probably came with an sei impeller. Get a oem merc impeller they last a long time. By long time i typically change them at 6 years ( freshwater, 40 hrs a year). my neighbors was ten years looked new
on the marine engine forum one of the professional marine mechanics on there says he swaps out new SEI impellers when he installs an SEI drive for a customer. Says the rubber separates from the hub.

 

[hopes&dreams83]

Retact, yes it did say "carburated 1999 5.0 mercruiser alpha1 gen 2."
but should not have had 2 post in same section

Yea it was a mistake I thought I was editing the original

 

[hopes&dreams83]

if its an sei drive probably came with an sei impeller. Get a oem merc impeller they last a long time. By long time i typically change them at 6 years ( freshwater, 40 hrs a year). my neighbors was ten years looked new
on the marine engine forum one of the professional marine mechanics on there says he swaps out new SEI impellers when he installs an SEI drive for a customer. Says the rubber separates from the hub.

OK I kinda suspected this. Is there anywhere to check for a blockage that could have caused this in the first place or just swap it out?

 

[hopes&dreams83]

No, it did not have the info, I deleted it and MOD's can still see it.

Pull the lower and check the impeller

The impeller is gone. No water is coming up from the transom connection when I run the boat for a few seconds. I have a new one coming tomorrow. I'm more or less just curious of why this happened so I can fix it once and avoid it happening again.

 

[hopes&dreams83]

No, it did not have the info, I deleted it and MOD's can still see it.

Pull the lower and check the impeller

The impeller is gone. No water is coming up from the transom connection when I run the boat for a few seconds. I have a new one coming tomorrow. I'm more or less just curious of why this happened so I can fix it once and avoid it happening again

if its an sei drive probably came with an sei impeller. Get a oem merc impeller they last a long time. By long time i typically change them at 6 years ( freshwater, 40 hrs a year). my neighbors was ten years looked new
on the marine engine forum one of the professional marine mechanics on there says he swaps out new SEI impellers when he installs an SEI drive for a customer. Says the rubber separates from the hub.

So you think it was just an impeller failure? No way the stuck thermostat caused this? Should I get the whole kit with the cover and orings or just the rubber impeller? I already ordered the merc impeller.

 

[Scott06]

The impeller is gone. No water is coming up from the transom connection when I run the boat for a few seconds. I have a new one coming tomorrow. I'm more or less just curious of why this happened so I can fix it once and avoid it happening again

So you think it was just an impeller failure? No way the stuck thermostat caused this? Should I get the whole kit with the cover and orings or just the rubber impeller? I already ordered the merc impeller.

No the thermostat would have no bearing on the impeller. Even with thermostat closed the cooling system is constantly flowing cold water to the exhaust system otherwise your manifolds, elbows, and rubber components in the drive and exhaust would melt. So the impeller always has a path to discharge water unless the manifolds elbows are clogged.

This is the kit I use, available from many sources.

MerCruiser Impeller Replacement Kit - Alpha 1 / GEN 2

MerCruiser OEM impeller replacement kit, fits: MerCruiser Alpha 1, Gen 2 (s/n 0D469859 & above) Mercury Mariner 40/45/50/60 hp BigFoot four stroke 60 hp, 2-cycle BigFoot (s/n OD000750 & above) 75/90/115 hp FourStroke 70/75/80/90 hp (3 cyl.) 2

www.michiganmotorz.com

There is a carrier assembly #19 in this parts dwg- need to inspect the top of it for deformation or heat damage. If the stainless housing is not scored I use some emery paper to get the light scoring, debris, and mineral deposits off and reuse it

https://www.marineengine.com/parts/mercruiser-sterndrive-parts/alpha-one-genii-1998-and-up/0l100040-up/gear-housing-driveshaft-standard-rotation

Really should just inspect it and water pocket up above and then buy parts. Willing to bet you will find an impeller that came off the center hub and is spinning freely of the driveshaft. Just seen a lot of comments on short life with non OEM (merc /Quicksilver) impellers. One thread the guy wanted to put a crank driven pump cause he got stuck out on the water. He was cursing merc engineers but using cheap off brand impellers.

Hopefully for you the impeller is the issue and you can move on.

 

[hopes&dreams83]

No the thermostat would have no bearing on the impeller. Even with thermostat closed the cooling system is constantly flowing cold water to the exhaust system otherwise your manifolds, elbows, and rubber components in the drive and exhaust would melt. So the impeller always has a path to discharge water unless the manifolds elbows are clogged.

This is the kit I use, available from many sources.

MerCruiser Impeller Replacement Kit - Alpha 1 / GEN 2

MerCruiser OEM impeller replacement kit, fits: MerCruiser Alpha 1, Gen 2 (s/n 0D469859 & above) Mercury Mariner 40/45/50/60 hp BigFoot four stroke 60 hp, 2-cycle BigFoot (s/n OD000750 & above) 75/90/115 hp FourStroke 70/75/80/90 hp (3 cyl.) 2

www.michiganmotorz.com

There is a carrier assembly #19 in this parts dwg- need to inspect the top of it for deformation or heat damage. If the stainless housing is not scored I use some emery paper to get the light scoring, debris, and mineral deposits off and reuse it

https://www.marineengine.com/parts/mercruiser-sterndrive-parts/alpha-one-genii-1998-and-up/0l100040-up/gear-housing-driveshaft-standard-rotation

Really should just inspect it and water pocket up above and then buy parts. Willing to bet you will find an impeller that came off the center hub and is spinning freely of the driveshaft. Just seen a lot of comments on short life with non OEM (merc /Quicksilver) impellers. One thread the guy wanted to put a crank driven pump cause he got stuck out on the water. He was cursing merc engineers but using cheap off brand impellers.

Hopefully for you the impeller is the issue and you can move on.

Turns out the impeller is fine. I replaced it anyway since I was in there and bought the part and kept the old one for emergency. Problem was actually the hose that goes from the gimbal housing through the transom popped off the gimbal housing. So I found that the pick up tube guide was burned and melted and also found an exhaust flap stuck after the Y pipe. Is there any more damage I should be specifically looking for that I'm missing? Also will the Y pipe or engine need to come out to Change the flaps?

 

[Scott06]

Turns out the impeller is fine. I replaced it anyway since I was in there and bought the part and kept the old one for emergency. Problem was actually the hose that goes from the gimbal housing through the transom popped off the gimbal housing. So I found that the pick up tube guide was burned and melted and also found an exhaust flap stuck after the Y pipe. Is there any more damage I should be specifically looking for that I'm missing? Also will the Y pipe or engine need to come out to Change the flaps?

The rubber tubes on the exhaust system between elbows and down elbows, and wye pipe. Wye pipe does t need to come out to change flaps (shutters), bute piece of them may have fallen down into transom housing .
how hot did the engine get? Would keep an eye out for water in oil if engine got hot, can blow a head gasket

 

[hopes&dreams83]

The rubber tubes on the exhaust system between elbows and down elbows, and wye pipe. Wye pipe does t need to come out to change flaps (shutters), bute piece of them may have fallen down into transom housing .
how hot did the engine get? Would keep an eye out for water in oil if engine got hot, can blow a head gasket

I dont remember but the exact temp but it was hot enough to make the buzzer come on. I shut it down immediately when it came on. Hoping for the best. It does start and run. I ended up rowing it back.

 

[hopes&dreams83]

I dont remember but the exact temp but it was hot enough to make the buzzer come on. I shut it down immediately when it came on. Hoping for the best. It does start and run. I ended up rowing it back.

As of now no water in the oil but no water was flowing when it happened so idk yet until I get it back together and see what happens