REPLACING MANIFOLD and RISER 3.0XL

[slh12639]

Ihave a 1997 MERCRUISER 3.0XL MEDEL NUMBER 4-30L100KS
SN OK277014. Very little water comming out of EXHAUST
and TEMP about 185 on mufs. Thanking about replacing
MANIFOLD & RISER. I have owned the BOAT three seasons
in salt water flush engine after each trip. Chances of
ringing BOLTS when removing them. Any help appreciated.
THANKS !!!

 

[Don S]

Re: REPLACING MANIFOLD and RISER 3.0XL

Have you considered replacing the raw water pump impeller to cure the problem?
I would sure try that before replacing manifold and riser. And I sure wouldn't replace them if they weren't bad. Have you taken the riser of and inspected the parts?

 

[slh12639]

Re: REPLACING MANIFOLD and RISER 3.0XL

I have replaced the impeller and the old one looked like
new.

 

[180shabah]

Re: REPLACING MANIFOLD and RISER 3.0XL

Like Don said, decide on replacing them yet, pull them off and look at them first.
You have replaced the impeller, how long ago, and what is it's condition right now. One encounter with a sandbar can toast a brand new one in minutes.

 

[slh12639]

Re: REPLACING MANIFOLD and RISER 3.0XL

Have only run on mufs since the impeller was replaced.
Back flushed a lot of pea sized rust.

 

[Don S]

Re: REPLACING MANIFOLD and RISER 3.0XL

Pull the riser off and LOOK.
No one here has a crystal ball to see inside it.

 

[Reel Poor]

Re: REPLACING MANIFOLD and RISER 3.0XL

No one here has a crystal ball to see inside it.

Now thats not all together true. I, for one, have seen you use this one on several occassions.
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[slh12639]

Re: REPLACING MANIFOLD and RISER 3.0XL

THANKS Reel Poor.

 

[Don S]

Re: REPLACING MANIFOLD and RISER 3.0XL

No one here has a crystal ball to see inside it.

Now thats not all together true. I, for one, have seen you use this one on several occassions.

Dude!!!! Did you save ALL the pictures I have posted in the past ? ? ? ? ? ? ?

PS: It's got a humongas crack in it. Seems I didn't have the proper manual for it and it now has freeze damage.
Am working with the OEM as we speak, trying to get the repairs done before the spring thaw......... :%

 

[Boatist]

Re: REPLACING MANIFOLD and RISER 3.0XL

I agree with all. On my boat when the manifold was going the motor would run hot 190 at full throttle but as I came down to half throttle of less would cool right down. On muff's always ran cool. My problem was the rust and scale from the from the manifold going bad plugged up the holes in the riser so could not get enough flow to to keep it cool at high RPMS. My manifold lasted about 12 years with about 50 percent saltwater use and always flushing after each use.

Check the flow comming into the engine from the impeller, Check the thermostat.