overheating

[dred1man]

hey guys i have a 1988 Capri 50hp force outboard motor (model) 507x8c/(serial) 3174, i hooked it up to the water hose let it run about 15mins before taking it out and the water was just spiting out of the 2 holes like it should but when i put it in a barrel of water not even 2min my buzzer sounds off and smoke comes from the 2 holes minus the spiting of water could this be a pump problem?

 

[pnwboat]

Re: overheating

Maybe. When you put it in the barrel make sure that the water level is well above the water intake. If it is, then yes it may be a water pump issue.

 

[Jiggz]

Re: overheating

As mentioned by PNW, if the level of water in the barrel was above the intake, the overheating is most likely caused by a faulty water pump. The reason it did not overheat while on the hose is due to the positive pressure provided by the faucet.

 

[dred1man]

Re: overheating

ok Jiggz/PNW and guys,,, thermostat is working right(stove method),took the impeller to boat store to replace mechanic said if water is flowing out while thermostat is out impeller is doing its job,and to check the compression, local mechanic checked both read 125 on both cylinders, barrel method well passed the intake, what else could it possibly be???

 

[pnwboat]

Re: overheating

Blockage in the water passages. The water passages in the exhaust cover are the smallest and not uncommon for corrosion (especially if motor was run in salt water) or sand or other debris to block those passages. Change the impeller first and see if that fixes it.

You can test for blockage while the lower unit is off. Take the hose and place it against the water tube that goes from the water pump to the block. With the thermostat out, you should get good flow of water coming out of the thermostat hole.

 

[oldboat1]

Re: overheating

Recommend replacing impeller as step one. While the lower unit is off, can do the flushing pnwboat suggests (good method).

forcing water up from the bottom is good for both testing and flushing, but need a reasonably tight fit around the water tube -- rig something using misc. hoses, water, fuel, whatever you have. If you have one of those quick release hose hookups for use in the garden, maybe use the small male end to step down the hose diameter, and connect from there to the water tube. Other listers seem to be trying to test or flush using a hose, and then complaining back online that the diameters don't match(!!). Anyway, it's a good method. (I use a manual transfer pump rather than a hose.) Leave the t.stat out when doing the flush initially to make sure water is getting up there, and can do a flush from there too. Additionally, you can pull the head cover and see whether and where the water is flowing around the cylinders. If the impeller change isn't enough, you probably have some corrosion in there in the water jackets, particularly if running in salt water -- and maybe some other debris (can be about anything, including remnants of mud wasp nests.) Once it's cleared and flowing, button it all up and replace the lower unit.

 

[Jiggz]

Re: overheating

ok Jiggz/PNW and guys,,, thermostat is working right(stove method),took the impeller to boat store to replace mechanic said if water is flowing out while thermostat is out impeller is doing its job,and to check the compression, local mechanic checked both read 125 on both cylinders, barrel method well passed the intake, what else could it possibly be???

So the question to the above is, was water flowing out without the t-stat while on in a barrel? If water was flowing then the engine should have not overheated while in the barrel. But based on your original post, it overheated while in the barrel but not while on the hose. If water flows while on the hose, it is not an accurate indication that the impeller is working properly. So this brings back the question, was water flowing while it was in a barrel?

 

[Justinde]

Re: overheating

Hi

This was what I found in my exhaust manifold when I replaced it....... Don't try and just take it off to have a look- the bolts are notorious for breaking- but, the sediment in my exhaust completely blocked the water flow and cause overheating.

Prior to this issue, by compression ( from memory) was 140/140/140/130 and I installed a new waterpump kit complete unit.

Don't know if this is applicable to you, and I don't know that you can check without removing the exhaust.

someone else for sure will have some further input or suggestions, however, this is what happened to me.

All the best;-)

 

[oldboat1]

Re: overheating

Nice, Justinde! good point about breaking bolts too (also head bolts). Best outcome would be for a new impeller to fix the problem, maybe with some flushing that doesn't require a wrench.

 

[MickLovin]

Re: overheating

Hi

This was what I found in my exhaust manifold when I replaced it....... Don't try and just take it off to have a look- the bolts are notorious for breaking- but, the sediment in my exhaust completely blocked the water flow and cause overheating.

Prior to this issue, by compression ( from memory) was 140/140/140/130 and I installed a new waterpump kit complete unit.

Don't know if this is applicable to you, and I don't know that you can check without removing the exhaust.

someone else for sure will have some further input or suggestions, however, this is what happened to me.

All the best;-)

You would think this bloke would do his flushing a bit better wouldn't you, That is bloody terrible Just should be ashamed of yourself
But seriously, this is also whats happens when it isn't flushed properly or the motor has been beached ( in other words run through sand bar ). Sorry Just thought I would get in first with this info, even though you told me first :laugh:

 

[pnwboat]

Re: overheating

Justinde, WOW......that one is probably the worst case I've ever seen!

Dred1man, this is about what yours should look like.

 

[MickLovin]

Re: overheating

Easy test for thermo, run it without it. still no flow, impeller or housing or what Justinde has said but you want it to be the impeller.

 

[jerryjerry05]

Re: overheating


Most people get these motors second hand and have no idea what the previous owner has done or not done.Don't throw stones.
Some people don't know what to do with an outboard after it's ran.
One of the worst I've seen(like Justins) was ran in fresh water.
Packed full of sand/weeds.
The bucket or barrell.Did the cavitation plate go under water?
DEEP ENOUGH??
Just to the plate isin't deep enough.
The water needs to be 2-3 inches OVER the plate.
Running on muffs,you need special muffs.
The pump housing what shape is it in?
Mine are probably original and look rough but still work good.
The wear plate on the pump??? What condition?
The pickup tube from the pump to the head.Is it blocked or loose.
Fill out the profile,location.
You might be close to someone who can help.