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Nothing is wrong...
https://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=14153		 Page 1 of 1
Author:  Haddock_ [ Mon Jun 22, 2015 3:33 am ]
Post subject:  Nothing is wrong...
Hi

Since I bought my '06 258 Vista it's not been achieving either top speed or intended max WOT rpms. I always wondered why. Over this winter I decided to find out. It has the 5.7 GXi-G 320hp engine with DP-SM drives that FW seems to favour. It revbed to approx 4400 with top speed of 32 knots on a good day, 31 the norm. It ought to do 37, so at least 400 rpms short and 5-6 knots.

Last year I replaced the external fuel filter, it was rated at max 50L/hr which is too little. Replaced with Racor 200L/hr 10microns. No difference in performance :( and less in my pocket.

First thing this year was to get rid of the filtermesh on the fuel regulator. Found some black rubber stuff on there but not enough to reduce flow. During this procedure I had to remove the flame arrestor...lo and behold...it was full of what looks like dust (as in you know dust bunnies from home). Found the ultimate way to clean out is pressure washing (water) from inside to push it out.

Haven't had a chance to try out what it meant until yesterday. With full vacation packing, twp adults, two kids, water and fuel tanks brimmed we easily reached 34 knots and 4800-4900 rpms before I easied off. Also noticeably quicker to get there. The loss of top speed is easier to identify as those measurements are usually all empty, smooth bottoms with no paint and in saltwater, 34 iand climbing is a great speed given the circumstances. I'm sure empty, no packing, factory spec batteries (I carry 2 extra) i would probably get 1-2 knots more, and that's in fresh water.

So conclusion - nothing was wrong, just eight years of dust buildup in the flame arrestor. I was ready to invest in a new motor...thinking the 450 hours it has on it was what one could expect. :)

Mike
Author:  LouC [ Mon Jun 22, 2015 5:56 am ]
Post subject:  Re: Nothing is wrong...
What I've seen is black dust that is likely from the drive belts because of rust on the pulleys. I clean it out with brake cleaner and dry with compressed air
Author:  Capt. Hoss [ Mon Jun 22, 2015 6:39 am ]
Post subject:  Re: Nothing is wrong...
Mine was the same way as Lou described, but I cleaned mine soaking in gas and let it air dry fro several days before I put it back on.
Author:  rpengr [ Mon Jun 22, 2015 7:49 am ]
Post subject:  Re: Nothing is wrong...
Haddock_ wrote:
... I was ready to invest in a new motor...thinking the 450 hours it has on it was what one could expect. :)

Mike

I sure hope not! I can't wait to see my hour meter well past 2000 hours. Then I know I got my money's worth out of it. :D
Author:  Haddock_ [ Mon Jun 22, 2015 8:18 am ]
Post subject:  Re: Nothing is wrong...
LouC wrote:
What I've seen is black dust that is likely from the drive belts because of rust on the pulleys. I clean it out with brake cleaner and dry with compressed air


Good description - drive belt dust :)
Author:  Haddock_ [ Mon Jun 22, 2015 8:19 am ]
Post subject:  Re: Nothing is wrong...
rpengr wrote:
Haddock_ wrote:
... I was ready to invest in a new motor...thinking the 450 hours it has on it was what one could expect. :)

Mike

I sure hope not! I can't wait to see my hour meter well past 2000 hours. They I know I got my money's worth out of it. :D


Yes well...i was ready and even posted on here about an engine upgrade. Now I don't need it :)
Author:  Vintage Beauty [ Mon Jun 22, 2015 12:23 pm ]
Post subject:  Re: Nothing is wrong...
LouC wrote:
What I've seen is black dust that is likely from the drive belts because of rust on the pulleys. I clean it out with brake cleaner and dry with compressed air


I clean mine that way... or I sneak it into the dishwasher when the wife isn't looking :) This works great!
Author:  LouC [ Mon Jun 22, 2015 2:35 pm ]
Post subject:  Re: Nothing is wrong...
Haddock_ wrote:
Hi

Since I bought my '06 258 Vista it's not been achieving either top speed or intended max WOT rpms. I always wondered why. Over this winter I decided to find out. It has the 5.7 GXi-G 320hp engine with DP-SM drives that FW seems to favour. It revbed to approx 4400 with top speed of 32 knots on a good day, 31 the norm. It ought to do 37, so at least 400 rpms short and 5-6 knots.

Last year I replaced the external fuel filter, it was rated at max 50L/hr which is too little. Replaced with Racor 200L/hr 10microns. No difference in performance :( and less in my pocket.

First thing this year was to get rid of the filtermesh on the fuel regulator. Found some black rubber stuff on there but not enough to reduce flow. During this procedure I had to remove the flame arrestor...lo and behold...it was full of what looks like dust (as in you know dust bunnies from home). Found the ultimate way to clean out is pressure washing (water) from inside to push it out.

Haven't had a chance to try out what it meant until yesterday. With full vacation packing, twp adults, two kids, water and fuel tanks brimmed we easily reached 34 knots and 4800-4900 rpms before I easied off. Also noticeably quicker to get there. The loss of top speed is easier to identify as those measurements are usually all empty, smooth bottoms with no paint and in saltwater, 34 iand climbing is a great speed given the circumstances. I'm sure empty, no packing, factory spec batteries (I carry 2 extra) i would probably get 1-2 knots more, and that's in fresh water.

So conclusion - nothing was wrong, just eight years of dust buildup in the flame arrestor. I was ready to invest in a new motor...thinking the 450 hours it has on it was what one could expect. :)

Mike


Most here feel that a well maintained marine GM small block is good for 1500 hrs if raw water cooled in salt, but they can go longer if flushed often and filled with AF with corrosion inhibitors when winterized. If closed cooled 2500-3000 hrs are not unheard of. In freshwater that's probably typical. The main thing is avoiding detonation (proper timing setting, spark plug heat range, and most important, not being over-propped). Over propping and leaking exhaust systems are probably the things that shorten the life of most marine engines.
Author:  Graham R [ Mon Jun 22, 2015 4:58 pm ]
Post subject:  Re: Nothing is wrong...
Vintage Beauty wrote:
LouC wrote:
What I've seen is black dust that is likely from the drive belts because of rust on the pulleys. I clean it out with brake cleaner and dry with compressed air


I clean mine that way... or I sneak it into the dishwasher when the wife isn't looking :) This works great!


I used to do that with engine parts and wheels; works great ! Like it doe for barbecue grilles etc

I can't do that with the D4 air cleaner, it's like an automotive paper air cleaner but of course significantly more expensive ! I do wonder about the real cost benefit of a diesel ! There's also an expensive crankcase breather filter, I'm tempted to ditch it and feed the outlet out of the transom; there can't me that much coming out of a modern diesel crankcase surely ?
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