Riser good or Bad

[B.matt]

i have a mercruiser 7.4l mpi , i pulled the manifold and risers off. How do you tell of the are good or bad. The openings do not look clogged and the metal appears to be thick. but there is a rust flaking of the water passages.
Thanks
B.matt

 

[MarkSee]

Re: Riser good or Bad

Pictures are always good but at least 1/4 inch thickness is what I remember the spec being between the different passages.
Also want to make sure the mating surfaces seem good and flat.

This is from a salt water boat?

Mark

 

[BigDog98]

Re: Riser good or Bad

i have a mercruiser 7.4l mpi , i pulled the manifold and risers off. How do you tell of the are good or bad. The openings do not look clogged and the metal appears to be thick. but there is a rust flaking of the water passages.
Thanks
B.matt

Well if it appears to not have a lot of rust inside of them then i would not really worry about it. However I would buy a heat laser gun and measure the temperatures of the risers and see if they are good. Generally risers must be replaced ever 3-5 years depending on the quality and brand of them. But pictures would be very helpful in this situation. If risers are not replaced and there appears to be a water restriction then it can cause water to fill up the head and cylinders. I know from personal experience. Hope this helped !

 

[B.matt]

Re: Riser good or Bad

I tried uploading pics and the file was to big. I measured the temps running at idle in 70 f water. The stbd was 98 and prt was 85. I purchased the boat in June and don't know when they where change last. The boat is run in salt water. Plan on adding the Volvo flush kit over the winter.

Thanks

 

[MarkSee]

Re: Riser good or Bad

The boat is run in salt water. Plan on adding the Volvo flush kit over the winter.

You posted this in the Merc. forum but you mentioned the Volvo flush kit.
Just want to be clear on which brand you got.

Mark

 

[fen-isl]

Re: Riser good or Bad

If you do a search on here you will find some threads that suggest using acetone. If i remember correctly it has less surface tension then water and there for will seep thru the rust in the manifolds and risers, thus telling you if they are in usable condition or scrap metal

Good Luck

 

[B.matt]

Re: Riser good or Bad

I will try the acetone and see what happens.
The vovlo flush kit can be used and a merc with bravo drive. i have been told it is a good system.

 

[BigDog98]

Re: Riser good or Bad

I tried uploading pics and the file was to big. I measured the temps running at idle in 70 f water. The stbd was 98 and prt was 85. I purchased the boat in June and don't know when they where change last. The boat is run in salt water. Plan on adding the Volvo flush kit over the winter.

Thanks

Sounds like the manifolds with that temperature are in not that bad of shape. Take the pics and crop them in a editor and then upload them. Or make a slide show of the pics you have and upload to youtube and post the link here. Then we can all give you a more detailed history on the manifolds and there condition. Good Luck !

 

[B.matt]

Re: Riser good or Bad


Uploaded Photos

 

[Bondo]

Re: Riser good or Bad

Ayuh,.... Replace 'em,.... The gasket surfaces are 'bout Gone, 'n already leakin',...

 

[Fishermark]

Re: Riser good or Bad

i The openings do not look clogged and the metal appears to be thick. but there is a rust flaking of the water passages.
Thanks
B.matt

Wow. Good thing you posted pics.

Those are toast! Replace those now before major damage is done.

 

[B.matt]

Re: Riser good or Bad

Thanks, I will change them, I am going to get oem mercruiser parts. The question I have is e-coated ok in saltwater or should I get the ceramic coated ones?

Thanks
Again

 

[B.matt]

Re: Riser good or Bad

The engine is seawater cooled

 

[Fishermark]

Re: Riser good or Bad

I boat exclusively in salt water and have come to the conclusion that it doesn't matter what coating, etc you put on things, they will rust and corrode. Period. Having said that, you might look into upgrading to a set of dry joint manifolds. I'm not sure exactly what needs to be done with them.... but I had a set on my last boat and they are excellent with a much longer life expectancy.

 

[pyrotek]

Re: Riser good or Bad

You might want to consider aftermarket as well. I think this is one area where a lot of people here use aftermarket for manifolds/risers where they generally use oem for everything else. I have had good results with mine. If you do decided to use aftermarket, you should use oem gaskets since the aftermarket ones use a different material (a dense paper/cardboard) for their gaskets. Certainly you can't go wrong with oem if you go that route.

 

[BigDog98]

Re: Riser good or Bad

View attachment 217467View attachment 217468View attachment 217469
Uploaded Photos

Yea you definitely want to replace those. They are horrible condition.Good thing you posted those pics!

 

[fen-isl]

Re: Riser good or Bad

I also boat in saltwater and switched to ceramic coated aluminum manifolds and risers they were 40lb lighter than the cast iron they replaced and come with 5 year warranty as long as you change the anodes once a year the coating is infused inside and out It also came with merc gaskets, new bolts and washers and thread sealant.

www.perfprotech.com

Just another option

Good Luck