Me too. But the type you’re talking about doesn’t help solve that problem lolI like motorboating.![]()
Me too. But the type you’re talking about doesn’t help solve that problem lolI like motorboating.![]()
nah. Stuff that requires minimal attention.What kind of plants?
View attachment 1715341096
The carbs need to be rebuilt first an foremost to get the engine running in normal heat balance. The overheating bit follows. That part is most likely the fresh water heat exchange pump and plumbing.So anyone here know boat engines very well? I am now the new owner of a 1984 Mercruiser . It was my grandmothers boat she got before her dementia got really bad a few years back. Today, my grandfather out of the blue gave it to my kids and I after we got back from a weekend on the lake. It’s been landlocked for nearly 4 years now with an over heating problem we cannot seem to solve. It’s an In-line GM 6 cylinder. 251 I believe. We’ve tried removing the thermostat and that didn’t help. Compression test came back A ok. It’s a water to water radiator system, sealed system of course. Water pump does appear to be flowing the coolant. No coolant leaks. No oil leaks, but it gets so hot so quickly it quite literally boils the gas in the carb. We have no way to run it out of the water. Anyone got any thoughts
Awesome thanks! Think putting a spacer between the carb and intake will help the heat soak any? I have plenty of clearance to do suchThe carbs need to be rebuilt first an foremost to get the engine running in normal heat balance. The overheating bit follows. That part is most likely the fresh water heat exchange pump and plumbing.
A closed system? It has a radiator? You sure? Rare to have. Most use lake or ocean water to cool.....So anyone here know boat engines very well? I am now the new owner of a 1984 Mercruiser . It was my grandmothers boat she got before her dementia got really bad a few years back. Today, my grandfather out of the blue gave it to my kids and I after we got back from a weekend on the lake. It’s been landlocked for nearly 4 years now with an over heating problem we cannot seem to solve. It’s an In-line GM 6 cylinder. 251 I believe. We’ve tried removing the thermostat and that didn’t help. Compression test came back A ok. It’s a water to water radiator system, sealed system of course. Water pump does appear to be flowing the coolant. No coolant leaks. No oil leaks, but it gets so hot so quickly it quite literally boils the gas in the carb. We have no way to run it out of the water. Anyone got any thoughts
Yep, surprised me too. Water is sucked in down by the prop, passes thru a pair water to water radiators, one on each side of the rear of the boat, then passing into the exhaust manifold, back out into the water. Each radiator is full of antifreeze and that flows to the water pump and into the engine. Lake water itself never enters the engineA closed system? It has a radiator? You sure? Rare to have. Most use lake or ocean water to cool......
No, just get the system operating as designed. It worked fine then and will now if you get it properly restored to the condition it was designed to operate in.Awesome thanks! Think putting a spacer between the carb and intake will help the heat soak any? I have plenty of clearance to do such
If i recall it has a heat exchanger.So anyone here know boat engines very well? I am now the new owner of a 1984 Mercruiser . It was my grandmothers boat she got before her dementia got really bad a few years back. Today, my grandfather out of the blue gave it to my kids and I after we got back from a weekend on the lake. It’s been landlocked for nearly 4 years now with an over heating problem we cannot seem to solve. It’s an In-line GM 6 cylinder. 251 I believe. We’ve tried removing the thermostat and that didn’t help. Compression test came back A ok. It’s a water to water radiator system, sealed system of course. Water pump does appear to be flowing the coolant. No coolant leaks. No oil leaks, but it gets so hot so quickly it quite literally boils the gas in the carb. We have no way to run it out of the water. Anyone got any thoughts
BUT you need lake water to cool the engine water. Water to water cooler. no lake water, no cooling.Yep, surprised me too. Water is sucked in down by the prop, passes thru a pair water to water radiators, one on each side of the rear of the boat, then passing into the exhaust manifold, back out into the water. Each radiator is full of antifreeze and that flows to the water pump and into the engine. Lake water itself never enters the engine
The lower unit has a pump, impeller if you want to get technical. Then it passed up a tube where its distributed through the heat exchangers. There should be a telltale that water is flowing, like the outboards have.Yep, surprised me too. Water is sucked in down by the prop, passes thru a pair water to water radiators, one on each side of the rear of the boat, then passing into the exhaust manifold, back out into the water. Each radiator is full of antifreeze and that flows to the water pump and into the engine. Lake water itself never enters the engine
Is there a way to test this on land? I thought about sticking the prop into a 55 gallon drum filled with waterThe lower unit has a pump, impeller if you want to get technical. Then it passed up a tube where its distributed through the heat exchangers. There should be a telltale that water is flowing, like the outboards have.
Correct.BUT you need lake water to cool the engine water. Water to water cooler. no lake water, no cooling.
So then, back flush the fresh water cooling system as a first step to blow out any contamination cloging it. Then repeat.If i recall it has a heat exchanger.
Screens in it. They get sanded up and no more cooling water.
ThisIs there a way to test this on land? I thought about sticking the prop into a 55 gallon drum filled with water
We run outboards on land all the time. Usually a garbage can.Is there a way to test this on land? I thought about sticking the prop into a 55 gallon drum filled with water
Awesome thanksWe run outboards on land all the time. Usually a garbage can.
The perfeshunals use a heating oil tank cut to fit the motor in.
Look at this^^^^^Chris
Will work depending where water intake is.
Down on the propWill work depending where water intake is.
Center of the prop is the exhaust.Down on the prop
That doesent really test the impeller. It forces water up through the exchangers.View attachment 1715341117
Both sides
Yep. But this also has a pair of flex tubes that run down to the prop as well. I guess they could be the water return. I’ll have to double checkCenter of the prop is the exhaust.