rt11002003
Well-known member
- Joined
- Dec 16, 2008
- Messages
- 720
- Fluid Motion Model
- C-24 C SE
- Hull Identification Number
- FMLT2113H314
- Vessel Name
- Loaf'N
I have 24.9 hours on the engine. After 10 hours I began to do short bursts (5 minutes) of max power every hour of operation. At first I could get 3375 rpm under load and 4000 without load.
Yanmar manual says our engine should be propped to always attain 3600 rpm under load and suggests propping to 3800 rpm so there would be room for additional load, etc. First, one needs to be sure they're reading exact engine rpm. Our tachs may not be accurate. A phototach reading of engine rpm may be necessary to determine our tachs' accuracy.
A second factor is that every vessel and every engine is a different testbed. My prop might be perfect in Mobile, AL and be off in Atlanta, GA. I don't know how much variance to expect, but once I have a baseline then I can decide whether I need to compensate if I see rpm changes in different places and under different conditions.
I haven't got that far because of other issues. At this point Andrew said he'd get in touch with Yanmar because Yanmar had told Ranger 3200 to 3600 rpm was OK. My concern was about the warranty. Yanmar can be picky about warranty, if you're interested try Google. I have not heard from Yanmar.
Andrew has told me of the effort Ranger has gone to in order to install a prop that best meets performance expectations. Everything he says makes sense. I don't care what rpm we're talking about as long the vessel performs and I don't have a warranty issue.
Back to the other issues; summer time on Lake Lanier brings out boats of all sizes and shapes. In some areas the wave action is a nightmare. I needed fuel just before the rush, so I introduced a different fuel source at that point. The engine operated as before, 3375 under load, 4000 no load. Later I needed to add fuel again, I was averaging about .6 gal per hour at that point, so I went went back to the same fuel source.
Then boat rush began and I wound up in some crazy, heavy waves. All long I was experiencing fuel/spray coming from the fuel vent. Now, (the lake is lumpy as late as 9:00 pm) fuel sloshing in the tank was forcing fuel out both the filler and the vent. Then my max rpm under load fell off to 3200, still 4000 without load. About a week later max rpm dropped to 3000, no load still 4000. I also think I'm feeling some engine surging, not enough to show on the tach.
What happened? I think my primary fuel filter is starting to clog. If so, why? The first fuel from the factory went thru many different temperature and humidity changes from Kent to here and could have been contaminated. I've gotten two fuel fills from a single source and it may be contaminated. The boat has been joustled hard enough for the fuel to erode the plastic from the tank walls. 😉
Went by the boat this morning to check and see what changing the filter would entail. Not much room to catch fuel from the filter housing, everything else seems right at hand. All I need to do is pickup some fuel to refill the filter housing, should have already had that on board.
Surging. I've had that problem on another Racor/Yanmar combination that I owned. The engine would run fine up to a specific rpm, then it would feel like the boat was slowing and the engine would stop unless I reduced the throttle quickly. Then it would run fine until I hit that rpm level again. After a couple of times I realized there was slight surging of engine rpm just before things got dramatic. Changed the filters, both primary and secondary. All that did was move the problem further up the rpm range. At that point I was selling the boat, (my wife felt we needed a larger boat) I explained the issue to the prospective buyer and changed the filters again. This time the problem moved up almost to max rpm. The fellow wasn't concerned since all was good in normal cruise range. I think he told me he used three or four filters on his nine day trip home.
Note: My present situation is the engine won't reach rated rpm, but whatever rpm is attained, it continues to operate, but may have slight surging. In the situation just described the engine would quit operating.
Aren't boats fun? 🙂
Gene
Yanmar manual says our engine should be propped to always attain 3600 rpm under load and suggests propping to 3800 rpm so there would be room for additional load, etc. First, one needs to be sure they're reading exact engine rpm. Our tachs may not be accurate. A phototach reading of engine rpm may be necessary to determine our tachs' accuracy.
A second factor is that every vessel and every engine is a different testbed. My prop might be perfect in Mobile, AL and be off in Atlanta, GA. I don't know how much variance to expect, but once I have a baseline then I can decide whether I need to compensate if I see rpm changes in different places and under different conditions.
I haven't got that far because of other issues. At this point Andrew said he'd get in touch with Yanmar because Yanmar had told Ranger 3200 to 3600 rpm was OK. My concern was about the warranty. Yanmar can be picky about warranty, if you're interested try Google. I have not heard from Yanmar.
Andrew has told me of the effort Ranger has gone to in order to install a prop that best meets performance expectations. Everything he says makes sense. I don't care what rpm we're talking about as long the vessel performs and I don't have a warranty issue.
Back to the other issues; summer time on Lake Lanier brings out boats of all sizes and shapes. In some areas the wave action is a nightmare. I needed fuel just before the rush, so I introduced a different fuel source at that point. The engine operated as before, 3375 under load, 4000 no load. Later I needed to add fuel again, I was averaging about .6 gal per hour at that point, so I went went back to the same fuel source.
Then boat rush began and I wound up in some crazy, heavy waves. All long I was experiencing fuel/spray coming from the fuel vent. Now, (the lake is lumpy as late as 9:00 pm) fuel sloshing in the tank was forcing fuel out both the filler and the vent. Then my max rpm under load fell off to 3200, still 4000 without load. About a week later max rpm dropped to 3000, no load still 4000. I also think I'm feeling some engine surging, not enough to show on the tach.
What happened? I think my primary fuel filter is starting to clog. If so, why? The first fuel from the factory went thru many different temperature and humidity changes from Kent to here and could have been contaminated. I've gotten two fuel fills from a single source and it may be contaminated. The boat has been joustled hard enough for the fuel to erode the plastic from the tank walls. 😉
Went by the boat this morning to check and see what changing the filter would entail. Not much room to catch fuel from the filter housing, everything else seems right at hand. All I need to do is pickup some fuel to refill the filter housing, should have already had that on board.
Surging. I've had that problem on another Racor/Yanmar combination that I owned. The engine would run fine up to a specific rpm, then it would feel like the boat was slowing and the engine would stop unless I reduced the throttle quickly. Then it would run fine until I hit that rpm level again. After a couple of times I realized there was slight surging of engine rpm just before things got dramatic. Changed the filters, both primary and secondary. All that did was move the problem further up the rpm range. At that point I was selling the boat, (my wife felt we needed a larger boat) I explained the issue to the prospective buyer and changed the filters again. This time the problem moved up almost to max rpm. The fellow wasn't concerned since all was good in normal cruise range. I think he told me he used three or four filters on his nine day trip home.
Note: My present situation is the engine won't reach rated rpm, but whatever rpm is attained, it continues to operate, but may have slight surging. In the situation just described the engine would quit operating.
Aren't boats fun? 🙂
Gene