• Untitled Document

    Join us on March 29rd, 7pm EST

    for the CBEC Virtual Meeting

    All EYO members and followers are welcome to join the fun and get to know the guest speaker!

    See the link below for login credentials and join us!

    March Meeting Info

    (dismiss this notice by hitting 'X', upper right)

Low Power? Low RPM'S? Excessive Smoke?- Try This Upgrade

Baslin

Member III
We bought our 1983 Ericson 38 2 years ago, and have plans of hopefully cutting the dock lines in about 3 years to go cruising. We got a pretty good deal on the boat so I knew there would be some work in getting her back in shape. The first thing I noticed was the engine would smoke at higher RPM's and had a difficult time getting up to cruising RPM's..(my Universal 5432 likes about 2200 to 2400 RPM's)....My initial thought was that it probably just needed a good service, change all the fuel filters, suck all the old diesel out and put in fresh fuel. After doing the service, same thing! No improvements that I could tell.

My next thought was maybe it was over propped. Once I checked the prop I found that it was way over pitched!...I believe from the factory, these boats came with a 15" diameter, 13 pitch 2 blade propeller...The one I had on the boat was a 16" diameter 2 blade and I cant remember the pitch...I thought to myself, That's It! Definitely gonna fix the issue with the new prop! While it was hauled out, we had a bottom job, I installed the new prop, splashed the boat and took off feeling very confident that our engine would blast off to 2500 to 2600 RPM's with no problem. We get out to the channel and I gave her some throttle. Engine sounded much better, it felt like it wasn't as overloaded and the RPM range did increase.......But not like it was supposed to, and still a large stream of smoke coming from the exhaust!!!

Back to the drawing board!...I then started thinking maybe the engine had some injectors that were misfiring or possibly low compression...The thought was always on the back of my mind but I thought for sure new fuel filters and the right sized prop would take care of the issue. I was wrong.

After researching injector pricing and glow plugs, I found I could buy all 4 new injectors from Kubota for $255 and new glow plugs for 7$ a piece. If I am going to pull injectors, then new ones are going back in for that price. I pulled all the injectors, performed a compression test, and to a big sigh of relief, the cylinder pressures were all in good range. Injectors and new glow plugs were installed and I'll be damned if there wasn't a single bit of improvement in the power and visible smoke. Well hell!

What to do now?....Lets see, a diesel engine is much like breathing. Air comes in, air goes out...What if the air coming in is the right amount, but the air coming out is more like breathing out one of those small coffee stir straws??...

Since we bought the boat, all of the repairs I made up to this point were in the plans of being done. Maybe not in the particular order I did them in, but they were still on the large "to-do" list.

The exhaust on the boat is a 2" out of the exhaust elbow, to the muffler, (which appeared to be made in 1907) and from the muffler, the hose was 1.5" all the way out. I upgraded to a Vernalift Centek 8" round muffler and all new 2" exhaust hose. Fired the engine up, much quieter, and it zips along with absolutely no smoke, and if needed, will reach about 2900 to 3000 RPM's!!!....The exhaust upgrade was about $300 and I can now rest easy knowing how much better the engine runs once it can breathe properly.

So if you have any low power issues, or RPM issues, the first thing I would do is upgrade the old exhaust system to a new 2" system from the elbow all the way out......Maybe just don't take the same road I went on.

Cheers,

Blake Aslin
 

HerbertFriedman

Member III
very interesting. My M25XP also will not rev up beyond about 2600 rpm. Had the mixing elbow changed, new filters, valves adjusted, some help but still will not rev up to factory specs. Engine has 2400 hrs and a well respected diesel engine group, who did all the above mentioned repairs, said that the engine was a bit "old and tired". I wonder if enlarging my exhaust system would help.
 

HerbertFriedman

Member III
originally I had thought to disconnect the exhaust hose from the output of the mixing elbow thereby by passing the muffler and connecting a hose directly out of the boat, any comments?
 

Baslin

Member III
very interesting. My M25XP also will not rev up beyond about 2600 rpm. Had the mixing elbow changed, new filters, valves adjusted, some help but still will not rev up to factory specs. Engine has 2400 hrs and a well respected diesel engine group, who did all the above mentioned repairs, said that the engine was a bit "old and tired". I wonder if enlarging my exhaust system would help.


It would sure be worth a try...the mufflers from centek are about $200 bucks and then about another $100 for exhaust hose and some fittings...if you suspect the engine may have some internal issues, then a compression test might not be a bad idea.
 

Baslin

Member III
Is there a test owners can do for engine exhaust back pressure?


I dont know of any test to check exhaust back pressure...i am curious as to whether the increase in exhaust hose helped my engine or whether there was a restriction in the muffler. I think i might try and dig it out of the dumpster and cut it open.
 

HerbertFriedman

Member III
It would sure be worth a try...the mufflers from centek are about $200 bucks and then about another $100 for exhaust hose and some fittings...if you suspect the engine may have some internal issues, then a compression test might not be a bad idea.

I would try this test but I cannot even see the muffler let alone swap it out. I guess I could try to just place the new muffler anywhere I can fit it temporarily and see how much difference it makes.
 

Kenneth K

1985 32-3, Puget Sound
Blogs Author
The exhaust on the boat is a 2" out of the exhaust elbow, to the muffler, (which appeared to be made in 1907) and from the muffler, the hose was 1.5" all the way out. I upgraded to a Vernalift Centek 8" round muffler and all new 2" exhaust hose. Fired the engine up, much quieter, and it zips along with absolutely no smoke, and if needed, will reach about 2900 to 3000 RPM's!!!....The exhaust upgrade was about $300 and I can now rest easy knowing how much better the engine runs once it can breathe properly.

The standard exhaust thru-hull fitting on most of the M-25 engined boats was attached to a 1.25" marelon ball valve. I believe the inner diameter of the "ball" on this size valve is only 15/16" in diameter.

Always mystified me that the exhaust line starts at 2" at the engine and winds up at less than 1" at the exhaust.
 

Tom Metzger

Sustaining Partner
The standard exhaust thru-hull fitting on most of the M-25 engined boats was attached to a 1.25" marelon ball valve. I believe the inner diameter of the "ball" on this size valve is only 15/16" in diameter.

Always mystified me that the exhaust line starts at 2" at the engine and winds up at less than 1" at the exhaust.

Most boats have the exhaust above the water line... no valve.
 
Top