Coolant Conundrum

bigd14

bigd14

Contributing Partner
Blogs Author
Prairie Schooner said:
The exit fitting on the riser is 1.99" OD. The input of the lift muffler has an OD of 1.71" and that's with some rubber hose on it to increase diameter. The output of the muffler is 1.65". The hose ID is 2.00".
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Such a frustrating cobbled together mix of hoses and fittings on these engines! It's a mess. I had the same problem. My lift muffler was delaminating so I had a new one made of stainless steel with the same input size as the exhaust riser output to simplify things. Of course I then complicated it again by adding a hump hose and a fiberglass elbow. I was going to try to match the entire exhaust system to the 2-inch exhaust riser exit fitting but I couldn't remove the exhaust thru hull without damaging the transom so I just kept it at 1.5 inches between there and the lift muffler.

If I were you I would probably replace all the hoses in the system to make sure they are not internally delaminating and are properly sized and clamped. Big painful job but worth it in the end.

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Loren Beach

Loren Beach

O34 - Portland, OR
Senior Moderator
Blogs Author
Perhaps worth a mention is that when we replaced the OEM Universal M25XP (23 hp) with the new Betamarine25 (25 hp), in 2018, the exhaust hose sizing was a bit bigger than the old hose and muffler bits. I was told that the newer engines have a larger ID exhaust hose to reduce back pressure and gain another fraction of a horsepower, but I am not an engineer.

I did replace the 1988 water lift muffler with a new one, same configuration and same company. New SS transom exhaust outlet, too. (sigh)
This did leave us with uniform hose and fitting sizing from manifold to transom, tho.

As for the original hose, it was starting to seep some rusty water from rusting of the steel spiral reinforcing, anyhow, and was surface cracking in sections. I figured that it "did not owe me anything" after all those years of service; it was going to get replaced with or without a new engine. Trivia: the factory Centek-Vernalift water lift muffler, like the replacement, was made of fiberglass, and cleaned up near-new. Good product, IMHO,
 
P

Pete the Cat

Sustaining Member
Christian Williams said:
It does look like the second hose clamp on several hoses was tightened outside the stub. That would certainly ruin a hose. Both clamps are supposed to be on the stub.

View attachment 51436
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You may find that the hose delaminated inside that hose--they are strong but do not like being compressed like that. I love my electric socket driver and 5/16th socket for working hoses. Saves time, skinned knuckles and improves my language.
 
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