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Test drive today, the boat ran better, and no jarring or stalling, but something seem strange. The engine ran at 4200 rpms, 38mph ,and 15.4 gph which seemed reasonable. moved to 3/4 throttle and 5000rpms, 43mph and 24.7gph. Moved to full throttle and stayed at the numbers just mentioned. The boat engine was tested to 5644rpm at purchase. Still seems like the engine is not getting the proper amount of fuel and GPH jumped 60% for 5mph! Any idea as too what is happening?
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what is a 300 supose to get at WOT?
use to you would just take 10% of the hp to get you close to GPH, but I have no idea if that changed on 4 strokesComment
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interesting.Originally posted by JimBen14 View Post
Well at least the ECM thinks its getting fuel -
that GPH value is just an electronic calculation:
rpm X injector "on time'
it assumes proper fuel rail pressure, and clean injectors
And everything was fine
until 'the mechanic' did this '100 hour service'?
Above you said "replacing the following: primary fuel filter, VST filter, and MAR fuel filter."
do you know what 'VST filter' he replaced?Comment
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Roscoe has always said the closer to 6000 the better. Trimmed to max level with whatever typical boat loading.Originally posted by 99yam40 View PostComment
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Test drive today, the boat ran better, and no jarring or stalling, but something seem strange. The engine ran at 4200 rpms, 38mph ,and 15.4 gph which seemed reasonable. moved to 3/4 throttle and 5000rpms, 43mph and 24.7gph. Moved to full throttle and stayed at the numbers just mentioned. The boat engine was tested to 5644rpm at purchase. Still seems like the engine is not getting the proper amount of fuel and GPH jumped 60% for 5mph! Any idea as too what is happening?Comment
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is there a reason you posted the same thing you wrote in post #16?
I do not know what boat you have but here is a performance bulletin on a 24'
https://yamahaoutboards.com/en-us/ho...ca_1-28-20-occComment
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I accidentally sent it 2x and I saw these performance numbers. I have a 2014 Scout XSF and these are numbers below from Scout. There were 2 people on board and 50 gallons of fuel. Some wind and only small chop as the conditions. Fuel line filter and the filter on the front of the motor were replaced.Comment
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Realized this chart may be hard to see. Scout chart is for same boat with a yamaha F250xca. 5000 rpm= 43 and 15.8gph, 5500rpm= 48 and 19.2, 6000rpm= 51,8 and 24.1.Comment
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Based on the fuel flow and online info, it sounds like fuel injectors. Does have anyone have comments? I understand this could be expensive?Comment
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Fuel injectors can be cleaned, inspected and tested generally for around $25 each..Originally posted by JimBen14 View PostScott
1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXRComment
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Forget about the reading of fuel flow. RPM is all that matters. Are you able to hit the same RPM as when the motor was new? As in 30-50 hours? Don’t over complicate this.
Fuel burn increases exponentially as the throttle moves past the “sweet spot”. Boat life.....
Last edited by pstephens46; 07-07-2020, 06:45 PM.Comment
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I appreciate everyone's comments! I bought the boat used and do not know. But, the boat engine was tested to 5644rpm at purchase with no over heating or any issues. I added a fuel additive/gas Starton, West Marine, fluid. I tried re trimming, up a little, the motor yesterday and was able to squeeze out of a few more mph, but the engine would not go past 5000 rpms. Still waiting on the tech to take a test ride.Comment
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Problem solved.. A kink in the fuel line was probably caused by the previous owner having the engine out of the water so much. Now running at 5600 rpms and 53 mph. Thanks for the comments.Comment
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Not sure on this engine where hi pressure test port is located. Older models, at the VST. Simple fuel pressure check will validate high pressure is at specification. This would rule out any high pressure pump concerns.Comment
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