Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 16-07-2013, 21:55   #1
Registered User

Join Date: Apr 2012
Posts: 75
Replace homeade? penta md7a exhaust riser/ elbow

Below is a picture of the exhaust elbow I just took off my engine to check for carbon buildup. I was surprised to see that it looks like it was made out of pipes from Home Depot. When I took it off about three pounds of rust can off when I remove the fiber wrap.

1. Is this an acceptable method of make a riser? If so what type of pipe should I use to replace it?

2. Seems that having one fabricated out of stainless steal pipe would be a better option, but I not looking to spend extra money not needed

3. With the water hose disconnected I used the starter to spin the engine to test the water flow. Anyone know how much water should flow? It had very little pressure - almost none. Should I rebuild the water pump while I am at it?

FYI - the engine does not run hot, runs cold if anything. Very little water come out the exhaust normally like spitting. The soot seems to be excessive because it makes my transom within a couple hours.

Thanks for any ideas!

Attached Thumbnails
Click image for larger version

Name:	image-3717012112.jpg
Views:	235
Size:	162.5 KB
ID:	64195  

jeffjd is offline   Reply With Quote
Old 17-03-2014, 19:55   #2
Registered User

Join Date: Mar 2014
Location: New Westminster BC
Boat: Windward 914
Posts: 13
Re: Replace homeade? penta md7a exhaust riser/ elbow

I've got the same engine. That riser is funky, but if it works, don't fix it. I think it is so high likely because your engine sits low, below water line. If the riser is below water line, you need that bend. If not...just a 45 bend and 8 inches of pipe with a feed welded on for the water and your done. That is what I did seven years ago and it has been fine. The paint hasn't even burned off.

As for water flow, there should be steady flow, but very low pressure. Remember that is a small fitting it comes out of. You should change your impeller every year or two. If it fails, looses one blade, it can really mess up the engine....I know, it cost me big bucks and two years of overheating grief until I found that little piece of rubber in the engine.

Greg Y is offline   Reply With Quote
Old 20-03-2014, 15:39   #3
Registered User

Join Date: Aug 2013
Location: big bend florida
Posts: 177
Re: Replace homeade? penta md7a exhaust riser/ elbow

I have had two boats with galvanized risers . Take a picture , draw a schematic , its easy to carry the pipe to replace or repair . No doubt stainless is better but it might take several weeks of wages to buy one . Just go to the Home Depot Marina
pistarckle is offline   Reply With Quote
Old 20-03-2014, 15:46   #4
Senior Cruiser
hpeer's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: Philadelphia
Boat: Murray 33-Chouette & Pape Steelmaid-44-Safara-both steel cutters
Posts: 4,149
Re: Replace homeade? penta md7a exhaust riser/ elbow

I have the same engine. Low flow is normal for me.

I just made two elbows out of SS. I bought the pipe and some 2 by 3 box section from online metals for about $125. Minimum quantities mean I had enough for two risers, so I made two. Haven't fitted it yet as motor is out of boat. Hardest part was drilling the holes in the 3/16" plate for the flange.
hpeer is offline   Reply With Quote

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:30.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.