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wmcunninghamii · 02-01-2021, 22:46

This is a very old thread so hoping someone is watching.

I have a 2 meter exhaust hose and a mere 57 inch run to the exhaust outlet on the transom. To make it work I have a big shortening bend in the exhaust which takes it close to the hull...too close for comfort. It is insulated (fiberglass wrap) but the hull is still getting warmer than I would like (about 190 degrees). I could eliminate all of this if I could shorten the hose. But how?

The hose has a smooth bit of tube either end about 3 inches long. The rest of the hose is corrugated. As a test I used a short piece of scrap tube and made a cut in the corrugated region and then tried to install this on the 24mm exhaust manifold on the heater. No way it will fit. I did my best to pound out the corrugation and circularize the cut end but was unable to get the ID I need to fit over the 24mm outlet on the heater.

Has anyone shortened one of these tubes and , if so, how did you accomplish it such that it would fit on the 24mm outlet?

CaptTom · 03-01-2021, 05:20

It's been a while, but as I recall, I was able to cut the flexible exhaust hose and it fit on both ends, the Planar and the thru-hull. I don't remember if I had to do anything to make it fit, sorry.

That said, I too was also uncomfortable with the fiberglass wrap insulation. I ended up using a product I found on Amazon by searching for "exhaust manifold insulation." Apparently it's used in race cars and such. Perfect for these Planars, because that exhaust pipe gets at least as hot as a race car exhaust manifold!

Still, you want the exhaust as short as possible. These things are designed to use in a truck or RV, with the exhaust going straight down just a few inches. A longer exhaust causes overheating and poor combustion, which plugs up the igniter and combustion chamber.

**newhaul** · 03-01-2021, 08:50

Quote:

Originally Posted by wmcunninghamii

This is a very old thread so hoping someone is watching.

I have a 2 meter exhaust hose and a mere 57 inch run to the exhaust outlet on the transom. To make it work I have a big shortening bend in the exhaust which takes it close to the hull...too close for comfort. It is insulated (fiberglass wrap) but the hull is still getting warmer than I would like (about 190 degrees). I could eliminate all of this if I could shorten the hose. But how?

The hose has a smooth bit of tube either end about 3 inches long. The rest of the hose is corrugated. As a test I used a short piece of scrap tube and made a cut in the corrugated region and then tried to install this on the 24mm exhaust manifold on the heater. No way it will fit. I did my best to pound out the corrugation and circularize the cut end but was unable to get the ID I need to fit over the 24mm outlet on the heater.

Has anyone shortened one of these tubes and , if so, how did you accomplish it such that it would fit on the 24mm outlet?

Simple its called a pipe stretcher. I know sounds like a joke but take the exhaust to a muffler shop and they should be able to cut and stretch the inner diameter for you.

**newhaul** · 03-01-2021, 08:53

Quote:

Originally Posted by CaptTom

It's been a while, but as I recall, I was able to cut the flexible exhaust hose and it fit on both ends, the Planar and the thru-hull. I don't remember if I had to do anything to make it fit, sorry.

That said, I too was also uncomfortable with the fiberglass wrap insulation. I ended up using a product I found on Amazon by searching for "exhaust manifold insulation." Apparently it's used in race cars and such. Perfect for these Planars, because that exhaust pipe gets at least as hot as a race car exhaust manifold!

Still, you want the exhaust as short as possible. These things are designed to use in a truck or RV, with the exhaust going straight down just a few inches. A longer exhaust causes overheating and poor combustion, which plugs up the igniter and combustion chamber.

Exhaust header tape . Sold in just about every auto parts store . Or order off Amazon.

I got mine off ebay
https://www.ebay.com/itm/22-24MM-EXH...edirect=mobile

goboatingnow · 03-01-2021, 09:04

Quote:

Still, you want the exhaust as short as possible. These things are designed to use in a truck or RV, with the exhaust going straight down just a few inches. A longer exhaust causes overheating and poor combustion, which plugs up the igniter and combustion chamber.

having installed 4 units , I fully agree, 1 metre is about the practical limit , the back pressure , especially on low settings , causes sooting and then bad ignition, longer runs would need some sort of scavenger blower

CaptTom · 03-01-2021, 09:22

Quote:

Originally Posted by newhaul

Exhaust header tape . Sold in just about every auto parts store . Or order off Amazon.

I got mine off ebay
https://www.ebay.com/itm/22-24MM-EXH...edirect=mobile

That's the stuff that came with it (and I ordered some more.) I didn't find it very reassuring. Inside a fiberglass hull behind some wooden cabinetry is a very different environment than under the hood of a car.

**newhaul** · 03-01-2021, 09:29

Quote:

Originally Posted by CaptTom

That's the stuff that came with it (and I ordered some more.) I didn't find it very reassuring. Inside a fiberglass hull behind some wooden cabinetry is a very different environment than under the hood of a car.

Header tape from your local speed shop