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To be clear your saying to drop lift down but leave engine tilted so prop is out if the water?
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No, just drop the motor enough so the prop and the cav plate are low enough to pump water, the test should only take a minute.Comment
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Just have the prop low enough in the water to get water in the pump if it looks like the boat will lurch forward and you cant stop that from happening don't try it.Comment
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My last word on the subject, then I'm out of here.....
I still don't see anywhere that it's been said that the engine is not running properly. Nowhere has the OP said that his engine misfires, or acts in any way contrary to how it should work. It runs fine at slow speeds (no wake speeds?), and it will rev to 4000rpm yet not get the boat to go over 10 mph at 4000 rpm. That's all that's been said. No indication that fuel delivery is a problem, no indication of coil breakdown, none of that!
Explain to me how a 115HP motor will not get a 17' 1700# boat to go over 10 MPH at 4000 RPM....whether the motor is running at peak performance or not. A 15" diameter prop seems a little big for that motor, but I could be wrong about that. But still, it seems to me that either he's into a great amount of prop ventilation, or the prop is slipping on the hub (yes, I know he checked that) or the boat weighs a hell of a lot more than 1700#.
Y'all have fun. I'm done.Mike
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Correct. No sign that the engine is not running properly. I’ve runs separate fuel tank directly to the pump ( circumventing tank,primer and water separator)with no improvement.Comment
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Hear where you are coming from….Originally posted by Harper View Post
I missed the earlier post re the 15” dia prop…. Thats crazy, I am surprised that it even fits under the AV plate!
Never heard of anyone running a 15” dia prop on a 115 or 140.
14” is the standard. On a 17 footer, a sensible starting point would be a 3 x 14 x 20 stainless. Maybe even a 14 x 22”
I know the OP said he has a 14 x 17, that will be nowhere near enough pitch. That said, the very early model 115/140’s did run a different final ratio so there is room for some variance there.
The big issue seems to be that at one stage, it planed and ran at speed with that 15” prop, if I read correctly?
That being the case, still sounds like an issue with engine….
Unless that prop has suffered some noticeable damage?
Or, the hull has excessive growth from sitting in the water, or
The hull has taken in water and is now far heavier as a result.Comment
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Harper, did you read post 7 he had the problem last year and it came good after a couple of runs, so that takes away over propped, it's on a lift so you would be able to see if it had growth on the hull, if the hull was cracked and it was getting water in, that would stop it from getting on the plane, but you would think you would see water coming out when it is on the lift.
If I was there in person, I would be able to diagnose his problem within one hour, but I am not I am across the other side of the world, I have to ask stupid unnecessary questions.
It sounds like a classic over propped, or over weight situation, if it wasn't for post 7, I would not have gotten involved in the topic.
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I know, Red. But even with post #7, "the same problem" would still be 10 mph @4000RPM. I appreciate your patience with the problem. I really just have no more to offer. No more ideas.Mike
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Red. In post 28 you say “ give it a squirt”. Please clarify to this uneducated guy.Comment
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If neutral is 12 o’clock. I engage in forward at 11:30 doing 1000 rpm. 3/4 mph. 11 is 2000 rpm. 6 mph. 10:30 is 3000 rpm going 8mph. 10 o’clock is 4000 rpm at 10 mph. 9 o’clock sugars between 4200 and 4000 no faster. Hope this may help. I made video but it’s too big to downloadComment
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I must be a glutten for punishment, all it means opening the throttle to max then come backdown to idle, put the boat in the water and lower the engine till the prop goes under the water just enough to pump water then push the throttle to the max and see if it goes over 4000rpm, put a picture up with your leg trimmed down so I can see how far below the bottom of the boat it goes.
Your engine should be able to do that easy I just want to know if your engine will go over 4000rpm with virtually no load on itComment
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I was not able to move throttle up while prop was in water to the cav. Lurched forward. Here is a pic showing throttle in WOT. Fully open. However....The circled area is a connection that was very loose. Any chance that could be part of the problem.
id be happy to take the prop off and test the squirt idea. ThanksComment
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I got more balls and gave it a good squirt in the lift with the leg in to the cav. I pushed the throttle wide open then brought it back to idle the rpm hit 2000. Took it for a spin and the loose connection didn’t help. Sorry but I try to send pic on my phone but it says it exceeds the 2 Mb max.Comment
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Well, for whatever reason, I'm hanging in on this thread, too. Let's try a different tack ....
In post #7, you said that last August it did the same thing then "cleared out after a few runs." To the best of your recollection, what was your WOT RPM and speed once it "cleared out?"
Also in post #40 you post RPMs and associated speeds. What are you using to measure the speeds? What kind of speedo shows 3/4 MPH?Mike
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Loose connection where, I asked you on page 29, have you checked and made sure the throttle plate on the engine is going to the wide open position when the shifter is moved forward to it's maximin position.
Try and post a picture of this loose connection.
Harper I thought you were over it. I hate starting something and not finishing it.
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