How long do exhaust manifolds and risers last?
The general consensus on raw water-cooled manifolds and risers is that they will last upwards of (6-8) years. Keep in mind that most if not all engine manufacturers do not put out a service bulletin on how long these maintenance items will last. Contents show How often do manifolds need to be replaced?
How long do boat manifold manifolds last?
Apr 09, 2020 · How long do manifolds and risers last? Risers on a FWC setup need to be replaced on the same timeline as a RWC setup, (6-8) years. For a FWC engine setup in theory the manifolds should last as long as the engine. Meaning if the boat is in a fresh body of water the engine and manifolds can last in upwards of 20 years. Click to see full answer.
How long do risers last in fresh water?
Feb 14, 2020 · Secondly, how long do MerCruiser risers last? about 4-5 years . One may also ask, how often should risers and manifolds be replaced? As a general rule, you should start inspecting your risers and manifolds thoroughly after having used them for two years. Many exhaust manifolds can last you between three and five years but factors such as the type of water you …
How often should I replace my engine risers and elbows?
Jan 05, 2008 · After 3-4 years pull a riser and inspect. Look for early leaking sign always though. (hard starts,leaking gaskets, WOT the temp increases, white smoke etc. Mine lasted 9 years in New England (salt water but only 260 hours) they still show no signs but it's time to just replace everything Jan 3, 2008 #4 KeithD New Member 149 Jul 16, 2007
How long do exhaust risers last?
The general consensus on raw water-cooled manifolds and risers is that they will last upwards of (6-8) years.Sep 1, 2021
How long do manifolds and risers last in freshwater?
Most experts suggest that a manifold will have a life expectancy of six to eight years. However, heavy use in saltwater can see this drop to as low as three years, while lightly used freshwater boats can get up to 20 years out of a manifold.
How often should Mercruiser manifolds be replaced?
Usually about 4 years.Jan 2, 2008
How long does a manifold last?
The intake manifold gasket on a car is supposed to last around 50,000 to 75,000 miles. In some instances, the gasket will fail before this date due to the amount of wear and tear that it undergoes on a daily basis.Jan 14, 2016
How often do you change manifolds and risers?
But they do need replacing every once in a while. Luckily, if you make sure they are properly maintained, you can increase the life span up to 10 - 20 years. On average, however, you'll have to replace them every 3 - 5 years.
How do you check a manifold and riser?
With the risers off you can see into the manifolds a little. Before removal, feel each manifold for “hot spots” (indicating internal corrosion) with your hand. Pros use a tool called an infrared pyrometer to diagnose manifolds. Secure disconnected exhaust hoses above the waterline to prevent sinking your boat!Mar 27, 2014
How do you know if the manifolds and risers need to be replaced on a Mercruiser?
The warning signs of a potential manifold or riser failure are elusive. Hard starting and an unfamiliar knocking sound on starting are two signs of a leak, but by then the damage is usually done.
Why do boats have risers?
All marine inboard engines have exhaust risers. The exhaust riser has two functions: (1) to keep water from backing up into the engine through the exhaust piping and, (2) it serves as the device that introduces cooling water into the exhaust exit piping system.
What is a marine engine riser?
Attached to the exhaust manifolds of the engine cylinders, exhaust risers act as the connection between the cylinder manifold and exhaust hose. The risers, sometimes also known as elbows mainly because of their horseshoe shape, are located near the top and along the side of the engine.Mar 18, 2010
When should I replace intake manifold?
In some engines, an intake manifold can corrode or crack causing either vacuum or coolant leaks. A cracked manifold must be replaced if it cannot be safely repaired. Coolant leaks: In some cars, there are coolant passages inside the intake manifold that can leak, often because of bad gaskets or other damage.Aug 1, 2021
Should you replace exhaust manifold?
A faulty manifold must be taken off and inspected, and replaced with new manifold. It's a large and complex part, so that can be expensive. So can labor, as the exhaust manifold is connected to the engine, which could make it quite difficult to access.Sep 29, 2015
When should I replace my exhaust manifold?
Engine performance issues and engine noise are signs to replace the exhaust manifold....Some of the most common parts that should be removed include:Engine covers.Coolant lines.Air intake hoses.Air or fuel filter.Exhaust pipes.Alternators, water pumps or air conditioning systems.Nov 18, 2016
How long do exhaust manifolds and risers last?
As a general rule of thumb, when used in saltwater: Dry Joint: 5-7 years, although recommend removal and inspection at 3-4 yearsWet Joint: Approx....
How long do diesel exhaust elbows last?
As a general rule of thumb, when used in saltwater:Stainless Steel: 10+ yearsCast Iron: Approx. 5 years, although some manufacturers recommend remo...
Will a low hour engine require replacement of the exhaust manifolds and risers?
Yes, it does not matter how many hours are on the exhaust manifolds and risers, they will wear out if used in saltwater and let sit for long period...
What are manifolds and risers?
Manifolds and risers are some of the less-discussed "consumables" on your boat. But when they corrode internally, they often destroy the engine. Illustration: Marcus Floro. Nearly every inboard and inboard/outboard (I/O) engine has exhaust manifolds and risers. But ask most people about the life span of these essential components, ...
What is the environment in which manifolds and risers live?
Manifolds and risers live in a harsh environment . They must endure very hot gas containing corrosive acids traveling at high velocity. They are exposed to saltwater and vibration, then left idle for long periods while rust and corrosion eat away at the metal and clog water passages.
What is an exhaust riser?
What They Do. Exhaust manifolds and risers are large metal castings that carry hot exhaust gases away from the engine on inboard engines. All V-8 and V-6 engines, for instance, have a separate exhaust manifold along the side of each cylinder bank.
How to tell if a manifold is leaking?
When the water jacket of a manifold or riser becomes clogged with scale and corrosion, a leak is usually close behind because the internal walls are deteriorating .
Why does water seep into the cylinders?
If water finds its way into the gas-only chamber before the end of the riser because of a leak in the water jacket , it can seep into the cylinders when the engine is at rest and either seize the pistons with rust or create a "hydrolock" condition.
How much does it cost to replace a manifold?
Replacing a riser or manifold typically costs several hundred dollars each, but failure to replace them when needed could cost thousands in engine damage. Any sign of rust in the gas-only chamber indicates a leak, which obviously warrants replacement, but it's more difficult to inspect the interior of a manifold.
What makes cast iron parts unique?
What makes these cast-iron parts unique is that they're pipes within another pipe. This double-wall arrangement allows hot exhaust gases in the internal pipe to be surrounded by water in the external pipe, called a water jacket, which should remain cool enough to touch.
chazaroo New Member
This is mainly a salt water question. I'm curious to know how long these things last on average. Secondarily how often do you re-torque risers?
SAshton Member
sounds about right. After 3-4 years pull a riser and inspect. Look for early leaking sign always though. (hard starts,leaking gaskets, WOT the temp increases, white smoke etc.
KeithD New Member
I bought my 2000 260DA over the summer with 140 hours and all original manifolds / risers, etc. There are no signs of trouble, but I'm having them replaced this winter to be safe.
fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor
Please use caution in accepting anyone else's experience as a standard for riser/manifold life. There are far too many variables involved for any one answer to be right.
SAshton Member
I agree with Frank. What aftermarket risers were you referring to that failed in 1 season?
Hampton Air Defense Dept TECHNICAL Contributor
Every Jan, 2008, and never before in my 15+ years of Merc ownership. 1st boat - 5.0 Liter with alpha for 4 years - Absolutely zero maintenance required other than fluids (lakes + trailer). 2nd boat, 1997 SR250 with 5.7L, BIII, and SS risers - 10 years, ocean + trailer - pulled manif/risers almost every year.
chazaroo New Member
I agree that an annual check is a good idea. And the gaskets are the problem most of the time from what I've heard. Also, the idea of periodically retorquing the riser bolts to spec may go a long way to solving the problems, according to my mechanic.
torcano
I just changed mine after 5 seasons. I would think that if you are flushing the engine and have a a neutra salt system you should be good for at least 5 seasons.
Hank
My manifolds and risers are original. I asked my mechanic two weeks ago about replacing them. He quoted me around the same price for the parts alone; around 800 deer. He was not insistent on replacing them.
torcano
It is my understanding that if you remove the risers to inspect them there is a possibility that they will not seat properly on the manifolds when you try to put them back. Once you put in the labor to pull them, it made more sense to me to just replace them.
jeff
Your mechanic is trying to pull a fasy one on you. Even if the riders and manafolds do need replacement, 4300 deer is WAY too much. As others have posted, the job is more like 1000-1500 deer per engine, with Volvo being towards the upper end of the 1500.
George290
i would like to think that if they are saying change them out, then they have them off and have looked in them. if so, can you go over there and take a look and see for yourself?
How long do salt water manifolds last?
Manifold. With raw-water-cooled engines used in salt water, you might expect their manifolds to have a three- to five-year life. Corrosion may warrant replacement in 10 years if an engine used in salt water has a closed cooling system. Riser.
Why do iron castings fail?
Iron castings, such as exhaust manifolds and risers, fail from corrosion as they cool and contract. Many a boat that runs well has been put in its slip on Saturday afternoon only to have water siphon from corrosion-damaged castings into the cylinders overnight.
Do risers fail before manifolds?
Even with a closed cooling system, the risers are raw-water cooled. Risers usually fail before manifolds do. Risers and manifolds used in fresh water have an almost indefinite life. Keeping an eye on the gaskets and checking the bolts for proper torque annually still makes good sense.
What is a manifold?
The manifold is a complex metal casting, actually a pipe within a pipe. It collects the extremely hot exhaust gasses directly from the engine into an inner "pipe" or long chamber which is usually cooled by raw water running through an outer casing.
What happens if water enters the manifold?
Manifolds and risers live in an incredibly harsh environment. They endure very hot corrosive gases slamming into the manifold at high velocity.
How long do saltwater boats last?
Most experts suggest that a manifold will have a life expectancy of six to eight years.
Why do water jackets vibrate?
All the time they're vibrating madly during running time and left idle for long periods, allowing rust to eat away at the metal. That they last as long as they do is impressive.
Why does my engine run white smoke?
If your engine is difficult to start, produces white smoke, or runs roughly, water in the cylinders may be the culprit. If you ignore the situation, hydrolock may occur. This is when sufficient water has leaked into the cylinder that piston compression becomes impossible.
Is a hassle manifold covered by insurance?
There is an additional hassle-manifolds are normally damaged by corrosion, so they're not covered by your insurance policy. All of this makes the outlook seem rather bleak. It's not as bad as it seems, though. All that's needed is a change in attitude.
Do exhaust manifolds last forever?
Exhaust manifolds last forever, don't they? Even if they do fail, it isn't a major problem, right? These are common reactions when people are asked about their boat's manifold. Unfortunately, exhaust manifolds are important, and ignoring them can potentially lead to expensive problems, perhaps an engine rebuild.
