[Jeffrey Cohen]

They are QSB 5.9 425HP

Really hard to get a good picture while in the boat but hopefully these get you want you need.

 

 

[Jeffrey Cohen]

Rob Schepis wrote:

Jeffrey Cohen wrote:
I mean the hose that comes off the bottom of the intercooler that powers the turbo.

Sounds like you mean hose #2. That is compressed air LEAVING the turbo compressor going thru the aftercooler and into the intake manifold. The only thing that “powers the turbo” is the stream of exhaust out of the exhaust manifold and into the turbo turbine.

Yes…I goofed that up.

Anyway, I went to the boat today and replaced both fuel filters on that engine (10 micron Racor and the 2 micron last chance filter on the engine). This had no affect so I took a closer at the silicon hose that unions the stainless steel tube to the turbo (blue #2 on the attached image) and it had a tear in it (I presume this was from the original hose clamp failure) which was the cause of secondary loss of power. I have since replaced it and all the clamps and now all is good.

Thank you all for your input and help.

Jeff

[Jeffrey Cohen]

Philip wrote:

And what’s the service history of the engines. Often times a hose that comes off the turbo to aftercooler connection is indicative of a clogging aftercooler. When was the last time the aftercooler was serviced and exactly how was it serviced? Also what are the condition of the connection hoses and clamps? At a minimum get a screwdriver on all the clamps and ensure all are tight. Consider new hoses and clamps if they are older.

Phil

I serviced them myself at the end of the season before last (1.5 seasons ~150 hours ago) as per Tony’s guidelines. This was my second time performing this work on the aftercoolers.

The hose clamp that came off just snapped in the middle…I probably tightened it too much as there was no corrosion whatsoever. I think it’s a good suggestion to start replacing the rest of the hose clamps.

Something similar happened at the beginning of last season right after i served the aftercoolers…except in that case I totally forgot to put back the hose clamp on the turbo feed side of the aftercooler on the starboard side. But in that case the engine operated perfectly after I reattached the hose. That is how I knew exactly what had happened.

Now I am trying to diagnose the elevated fuel burn on that engine. I have no idea if it is related or it’s just a coincidence.

Thanks for the input and suggestions.

Jeff

[Jeffrey Cohen]

As to the the one on the engine–if it was me , I’d dump it into a clean bowl and “look & see”.. Then, I’d cut it open and “look & see”..

Will do

[Jeffrey Cohen]

Rob Schepis wrote:

Did you mean a boost hose? Air intake coming off the turbo?

Post your fuel burn numbers at cruise range rpm’s and WOT rpm.

Do you have data of “X speed at X rpm” ? – both historic and now?

Post some good pictures of your engines, the installation and the exhaust.

BTW, not following your format of Day 7, Day 1, today ..

I mean the hose that comes off the bottom of the intercooler that powers the turbo.

My boat has been very consistent since the day I launched it….
2500 RPM
25 GPH (12.5 GPH each engine)
25 Knots (SOG)

Right now, at 2500 for each engine, I am seeing 14.5 GPH for the port engine and 12.8 for the starboard engine but the port engine is not settling in (keeps hunting around 2500 +/- 30 RPM) so the starboard numbers are suspect.

As for the format…. Day -7 was last weekend return to home port Day -1 was yesterday and today was today.

I’ll report back on once I replace the fuel filters on the port engine and check all the hose clamps and clean the airsep. I will grab some pics too.

Thx
Jeff

[Jeffrey Cohen]

Unfortunately, other than zincs this heat exchanger was not maintained or fresh water flushed. I pulled it because there was evidence that the end cap gaskets were giving way as well as the impeller pieces.

That being said it seems to be in pretty good condition but I won’t know until I pressure test next week.

Either way I might just replace it and not have to worry about it for the next 9 years and if I can figure out a way to flush it each weekend I will.

Thank for the responses

Jeff

[Jeffrey Cohen]

the line represents the area where the engine has oil on it as opposed to some light spray.

Anyway the belt guard is off (otherwise I would probably not even know about this issue yet) but there is only about 6″ between the front of the engine and the bulkhead so pictures will be difficult but I will try.

If I had to change the main seal is this doable without pulling the engine?

[Author]

Replies