Manifold replacement

[rynosback]

I have a 2002 Crownline 202 bowrider with the Volvo 4.3L GXI engine(fuel injected). The boat is run in brackish water. The boat started to over heat a little at the end of this season and I have determined that the exhaust manifolds are clogged. So I am happy with how long the OE manifolds lasted. So these are my questions

1. Should or do I need to replace the risers at the same time?

2. I was thinking of going after market because of the cost difference, is there manufacture that is recommend over any others?

3.Is there a shop manual on line that I can down load for free? I need the torque specs.

Thanks for your input and knowledge.

 

[redjmp]

Re: Manifold replacement

Ok first off, how do you know its the manifolds?

Manifolds usually last longer than 8 years even in salt water.

Risers on the other hand only last about 5 years or half as long as a manifold.

I would try to pull the risers first as they are probably your culprit after 8 years.

The manifolds I would probably try save but I would pull them as well and I would give them a few moderate blows with a hammer to loosen off any scale, then I would blast them with a pressure washer and poke around with a long screwdriver to get all the gunk out.

Manifolds don't take too much torque.

20 lbs if memory serves me...

Osco and Aqua Power make decent manifolds/risers.

GLM are hit and miss...

 

[rynosback]

Re: Manifold replacement

Ok first off, how do you know its the manifolds?

Manifolds usually last longer than 8 years even in salt water.

Risers on the other hand only last about 5 years or half as long as a manifold.

I would try to pull the risers first as they are probably your culprit after 8 years.

The manifolds I would probably try save but I would pull them as well and I would give them a few moderate blows with a hammer to loosen off any scale, then I would blast them with a pressure washer and poke around with a long screwdriver to get all the gunk out.

Manifolds don't take too much torque.

20 lbs if memory serves me...

Osco and Aqua Power make decent manifolds/risers.

GLM are hit and miss...

When I winterized the boat I put my finger in the hole and felt that it was packed with crap.

 

[redjmp]

Re: Manifold replacement

They usually are! You should stick a screwdriver up there to make a passage for them to drain.
But that is normal and not necessarily an indication that they have gone bad.
It just happens to be where any loose rust and scale collects.

 

[Lola22]

Re: Manifold replacement

1. Yes

2. Osco

3. I just replaced them on my VP 5.0. Torque was 12-18 on the risers and 20-26 on the manifolds.

It was the first time I had done this and it was a much easier job than I expected. Get a longer bolt and cut the head off to make getting manifolds on easier.

 

[zbnutcase]

Re: Manifold replacement

Have you replaced the impeller lately?

 

[littlebookworm]

Re: Manifold replacement

There's been quite a few threads here and on BoaterEd.com on how and when to replace manifolds and risers. Most people replace both at the same time. Much has been said about drawing a file across all the mating serfaces of the manifolds and risers to insure flat surfaces. The extra long, headless, bolts are a neat trick to hold up one end of a manifold as you secure the other end. Again, check previous threads. My motto: Even though they're expensive, if in doubt - replace. Bad manifolds or risers can kill your engine. Hy

 

[rynosback]

Re: Manifold replacement

Have you replaced the impeller lately?

I replace it every two years. I also just put a new one in and it did not look that bad either.