HELP changing impellor mercruiser 260????

[bigchunkytaco]

need help replacing impellor ive got twin mercruiser 260 v8 inboard cooled to vdrives shafts with serial #6703143 and #A608492

firstly i need to figure out the model number so i can order a replacement kit, secondly is there any easy way to get the pump housing off as its in a really hard spot... can i do it at the back without taking the pulley off?

and also being that the raw water intake is on the bottom of the hull with no shut off **** can i do it in the water or will i flood the boat... in the picture those little buckets are the water filters and are the highest point of the water lines, the bottom end is the intake from hull the other goes through the v drive and then the water pump.
im thinking if i disconnect that first it should be above the water line and i can tamper away with the pump?

thanks in advance

 

[alldodge]

Re: HELP changing impellor mercruiser 260????

need help replacing impellor ive got twin mercruiser 260 v8 inboard cooled to vdrives shafts with serial #6703143 and #A608492

firstly i need to figure out the model number so i can order a replacement kit, secondly is there any easy way to get the pump housing off as its in a really hard spot... can i do it at the back without taking the pulley off?

and also being that the raw water intake is on the bottom of the hull with no shut off **** can i do it in the water or will i flood the boat... in the picture those little buckets are the water filters and are the highest point of the water lines, the bottom end is the intake from hull the other goes through the v drive and then the water pump.
im thinking if i disconnect that first it should be above the water line and i can tamper away with the pump?

thanks in advance
View attachment 206148

Need to know the year of your engine/boat. Measure the incoming water lines and determine what size is the ID of the hoses. Find valves and fitting sizes which best suit the hoses needed to close off the hoses. Pick up different sizes if needed to have all sizes on hand. Place a electric sump pump (the biggest you can find) or even rent one better yet, with a high volume. Have rags, wood plugs and such but don't worry if water starts comming in so long as the hose you take off has the ability to be raised above the depth of the water the boat sits. Take the hose off and raise above the depth of the boat, find the valve and fittings needed to seal off the hose. Once this is determined, have the valve and fittings put together and you can then cut the hose from the fitting suppling water coming in. Make sure your sump pump is already in the boat. If the incoming water gets to much for you have rags available to close off hose until sump pump empties bildge. Have hose clamps and tools ready and have help.

Keep in mind if someone is available to go under the boat and place a rag/towel over the water intake port the water will be reduced greatly. Do this one at a time until both have valves in place then shut water supply off and work on pumps.

 

[achris]

Re: HELP changing impellor mercruiser 260????

From the serial numbers, one of the engines is 1984 (6703143) and the other is 1986 (0A608492). With Mercs the most important information is those serial numbers, not the year. From the serial number we can determine year, but some time people tell us a year and ask for some information and it doesn't make sense. We then ask for the serial number and find out that the engine is actually not even close to the year they tell us, so always, the serial numbers.... We basically consider the year of the engine as speculation and hearsay... (until we can verify that with a serial number )...

So, on to your questions.

As long as the strainers are above the waterline, then you should be ok to disconnect them. I would install a couple of plugs just to be on the safe side, but that's me...

AllDodges advise on fitting shut-off valves to the incoming line lines is excellent. I'm quite surprised valves aren't already in the lines anyway.

As for the dis-assembly of the pump. From what I can see, you should be able to remove the back of the pump and leave the pulley and pulley bearing attached to the brackets/engine. Once you have the pump body out you can service it according to the type you have (one piece or two piece). I have attached the service information for those 2 pumps.

Chris....

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

appreciate all the info! successfully pulled water pump and will rebuild once i get an impellor kit.
i also pulled the riser that wasnt flushing any water and it was almost entirely blocked and full of corrosion....
as a short term fix can i get away with just replacing the riser or will the manifold be just as bad on the inside and not work even with a new riser???

 

[alldodge]

Re: HELP changing impellor mercruiser 260????

appreciate all the info! successfully pulled water pump and will rebuild once i get an impellor kit.
i also pulled the riser that wasnt flushing any water and it was almost entirely blocked and full of corrosion....
as a short term fix can i get away with just replacing the riser or will the manifold be just as bad on the inside and not work even with a new riser???

I'll guess the manifold is just as bad if not worste; that being said I'm sure it will help to replace just the riser, but I would replace both. From their condition they have probably been in place a long time.

 

[achris]

Re: HELP changing impellor mercruiser 260????

Generally the metal is thicker on the manifold that the elbow. That said, I would replace both if there is any doubt. It's quicker and easier than replacing an engine if it leaks and damages the engine.

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

i thought as much, would i be right in assuming that the other manifold and riser on the same engine is probably in the same condition even though its pumping plenty of water? (and more than likely the other pair on the other engine...)
i was kind of hoping that replacing the riser would get me by for a while until i can replace all 4 sets of manifolds and risers.....

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

i should have mentioned that it is a closed water cooling system with a heat exchanger so i think the raw water only pumps out through the riser and not the manifold??

 

[achris]

Re: HELP changing impellor mercruiser 260????

Some closed cooling systems only do the engine block, intake manifold and heads, known as a 'half system'. The one that includes the exhaust manifold is known as a 'full system'.

When you removed the exhaust elbow did the gasket between it and the manifold look like this....

Or this....

Chris....

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

ah ok, pretty sure it was the top one, there was green radiator coolant in those middle passages which is what made me think it was fresh cooled....

 

[achris]

Re: HELP changing impellor mercruiser 260????

???? The top gasket is for raw water cooled or half closed systems. it allows seawater to run up through the manifold and into the elbow for flushing out in the exhaust system.

The bottom gasket closes the water in the manifold from the seawater in the elbow. If you saw green coolant in the manifold water jacket, then the gasket should have been the bottom one...

Chris........

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

i may have been thinking of the top of the manifold having coolant sitting in the passages... this gasket looks closed unless its just clogged with crap, does the closed system literally come right up to the gasket of the riser? and is this called a wet joint riser?

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

i sourced a couple of mercruiser parts $350 for a riser and $110 for a pump repair kit, this riser along with one of the others is an aftermarket brand "osco" being a fellow aussie was wondering if youd know where to get these or any aftermarket bits so i dont have to buy genuine merc... cheers

 

[achris]

Re: HELP changing impellor mercruiser 260????

Those gaskets are most definitely a full closed cooling system.... Given that, your manifolds should be fine. As for parts, it's really difficult in Oz. We get ripped no matter who you're buying from....

Chris.....

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

champion. i sourced a glm riser a bit cheaper, the bloke also sold me 2 gaskets that look closed but the "block off plate" that goes with them looks like its open (the same as the top gasket picture you posted) it does say "block off plate" on the wrapper but you would think it should match the gaskets and close the riser from the manifold.... just thought id check before i goo it up with sealant

 

[achris]

Re: HELP changing impellor mercruiser 260????

I would also think the 'block-off plate' should not have flow-though holes. That said, my old V6 was full closed cooled and the separation between the top of the manifold and the elbow was just the gasket, nothing else... And that engine is still going, with SS elbows and closed cooling, the manifolds and elbows haven't been looked at for over 10 years, still like new when I dropped the exhaust tubes to check the shutters...

Chris.....

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

nice i might go back and swap it out anyway.. got the pump back on so once i get the riser in there hopefully problem solved, although the old impellor looked in pretty good knick to me so hope its not something else... cheers for all the help definately a "supreme mariner"

 

[bigchunkytaco]

****OVERHEATING merc v8??

****OVERHEATING merc v8??

ok so port engine started to overheat, i have replaced impellor, thermostat and riser as it was restricted... i am now getting water out the exhaust flaps and plenty of raw water through the intake but its still gets hot?? it is a half closed system so the manifolds and engine are fresh water cooled...

could it be the heat exchanger or the head gasket? any ideas i am lost.... cheers

 

[jackd1023]

Re: ****OVERHEATING merc v8??

Re: ****OVERHEATING merc v8??

what engine/drive?

 

[bigchunkytaco]

Re: HELP changing impellor mercruiser 260????

didnt work... i have replaced impellor, thermostat and riser, im now getting water out the exhaust flaps and plenty of raw water through the intake but the bastard still gets hot??? should i sink it? i think i should sink it