Incorrect Prop or Motor Malfunction?

danjb

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Please scroll to my latest post... same issue, same thread, but what I originally posted here is no longer here..? Not sure why not, but I rewrote the problem down there.
 
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ondarvr

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I have a 19' Blue Wave Classic without the tunnel, I put a older 50HP on it one time and if I did everything right and surfed down a wave I could get it on plane, so the 16' should do it easily with a 60. I've heard the tunnel makes it harder to dial in though.

​Revving the motor out of the water and in neutral doesn't mean anything, it can be running terribly and still get over 5,000 RPM's with no load.

The throttle plates do need to open up completely, plus it needs to push the timing linkage to the stop.

​Make sure the bilge is empty, it can hold water. you can weigh the boat to see if the foam is waterlogged.

​I would get the boat as light as possible and see if it will plane, then record the RPM's to see if you're in the right range at WOT. This will let you know if a lower pitch prop is needed. But his only applies if the motor is running correctly.
 

SkiDad

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I'm showing a posible 1.85 gear ratio on that engine - if so, that is high so I would try a smaller pitch prop - say a 11 or 12 pitch
 
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Starcraft5834

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Agree with Admiral...

"​I would get the boat as light as possible and see if it will plane, then record the RPM's to see if you're in the right range at WOT. This will let you know if a lower pitch prop is needed. But his only applies if the motor is running correctly."

last line says it all. But this only applies IF the motor is running correctly.... if lightly loaded and you still cant get on plane, the motor is likely tired.. if so, you can reduce pitch for more punch... there's only so much punch in the bowl tho :) good luck
 

Sea Rider

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Carbs and timing advance must be set at their max factory adjustment specs in order to get the max out of both settings working together. When sure about OB is running top, check if current indicated prop is not spun, for that will need to perform a hub test. Then will know if OK to move to a less prop pitch.

If current prop is found OK, to get the most out of that 60 HP will definitely need a state of the art prop maximization to run at its max wot rpm range (usually 6 K as usually loaded) if possible as your OB is under powered if it's transom rated for a 90 HP.

Happy Boating
 

Scott Danforth

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Mount – Highest hole. Plate is just above top of tunnel. Will not go down further.


take a picture of the back of the boat with the motor in the down position so we can see the anti-cav plate and the tunnel.

you may have your motor down too much

[FONT=&quot]I recently purchased a “new to me” boat and put a “new to me and to boat” motor on it. I got it all put together and took it for a test drive on the lake. When increasing throttle from idle/slow speed to planning speed, motor digs in and will not get the boat moving fast enough to get on plane. Calm day, but RPMs peaked at 3100 and 2800 constant before I backed off. Motor will continue to push boat at this rate w/o stalling out. Speed could not have been more than 10-15 mph… didn’t look at gps, but boat would not get on plane so speed is an assumption. Trimmed in, trimmed out, no change.


this tells me that either the motor isnt pushing enough torque, or the motor is buried too deep or too high of a pitch prop. because your lugging the motor, we know that the prop hub isnt spun.

check to see what the new to you boat weighs and compare that with the specs. http://boatspecs.iboats.com/Blue_Wave_Boats_by_Parks_Mfg.__165_Super_T__1998/bp/66b163153
 

danjb

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danjb

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Thanks for all responses... from what I gather this is my course of action:
1. Bilge is dry. Boat hasn't been on the water for 4-5 months before this test... so hopefully foam is dry. But, it's foam and I'm sure it can stay saturated for a long time. I'll say that when I had the boat torn down, I could easily slide all 850lbs of it around on the trailer.
2. Take to mechanic to check: 1. carbs and timing. 2. set carbs to max factory setting and advance timing to max factory setting 3. make sure throttle & shift cables are dialed in... I can remove replace anything, but really have no expertise in adjusting timing and carbs. So, we'll let an actual mechanic tell us that motor is running at its optimum.
3. Go back to lake for 2nd test run. Trim down and see if it'll pop up on plane. For this, I'll take out any non-essential weight (trolling motor batteries, drain main fuel tank, etc.) Will do test run with portable tank & different primer & fuel lines (so we can rule out fuel restrictions). If it does get on plane, I'll record rpms and speed in 500 rpm increments from dropping off plane to 5500 rpms even 6k rpms, if it'll get there.

I didn't see a conclusion on prop from dingbat's forum link. In the meantime, please advise if I'm needing the mechanic to check for anything else. Also, I've posted the few pics of motor on the boat.
Side note. Prop is new and tight. Manual says gear ratio is 2.33 (28/12)
 

Watermann

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Too much prop is my assumption and I'm thinking yours too since yo're here in the prop forum. My best guess is that you need a 13"p prop for that size boat and motor combo. A 60HP motor that is showing it's age would not be able to turn that pitch of 4 blade SS prop. Personally if it were me I would put on a aluminum 3 blade on that motor in a 13p, I bet you would be amazed at what will happen.
 

ondarvr

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1. Bilge is dry. Boat hasn't been on the water for 4-5 months before this test... so hopefully foam is dry. But, it's foam and I'm sure it can stay saturated for a long time. I'll say that when I had the boat torn down, I could easily slide all 850lbs of it around on the trailer.
(28/12)

​If the foam was waterlogged you would need to keep the boat in Arizona for 4-5 years for it dry out much.

​The design of the Blue Wave bilge helps avoid waterlogged foam though
 

jakedaawg

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A simple test to see if your motor is doing its work would be a cylinder drop test. With motor under mild load pull off one plug wire at a time and hold it near a head cover bolt. You should notice a change for each cylinder. Those 60 yamy's can be a little tricky for some.
 

danjb

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Hello again... I've done a lot of testing and am still not at max operating rpms or on plane. I didn't see my original post show up at the top of this thread, but the problem is that i cannot get this motor to push this boat..? It's just plowing water and won't plane... or if it is on plane, it's so subtle you cannot tell.
Boat 1998 Blue Wave 165 Super T (originally sold with Evinrude 50hp 2 stroke mounted all the way down)
Motor 2004 Yamaha 60hp 2 stroke.. 60TLRC
Prop 4 blade stainless 14 pitch 13 1/4" Yamaha K series

I'm completely discouraged at this point, but here's where I'm at after posting this thread last year:
1. Took motor to mechanic, everything checked out fine.
2. Borrowed prop from him 3 blade 15 pitch.. no plane
3. Went to prop shop.. 3 blade 13 pitch, 3 blade 12 pitch, 3 blade 11 pitch all no plane
4. Raised motor to highest hole on transom, better rpms, but no plane.
5. Put on a permatrim. No change.
6. Got a fixed jack plate (TH marine hi jacker) moved motor all the way up. Still better but still plowing water.
7. Took motor to big boy boat/Yamaha dealer. They said carbs are dirty and motor deprived of fuel. They did carb job and confirmed that motor is getting up to 5500rpms in test tank (by the way, what does that even mean? Does a test tank put an actual load on a motor?)
8. Back to lake this past weekend. Completely new ethonal free fuel and carb job. Most i could get before losing grip from trimmimg up is 4300rpms/23mph. That felt amazing, but still seemed like it's not popping up on plane, or if it is, it just going really slow. I know 23 is pretty good for that motor on that boat, but I'm thinking rpms should be up around 5200-5500. Im losing all my top end rpms. Basically pushing the boat like a 40hp motor would.

What should I try next?

I have a new fuel pump coming tomorrow. I also bought a new 6 gallon fuel tank and fuel line. After this past carb job, I did find that there was very very minimal room for adjusting carb butterflies to wide open. I mean just a slight amount. I adjusted it, but would like to think that the dealer did appropriate link and sync and made necessary adjustments...?
If it's fuel restriction, what else can I check?
Should I go up in prop pitch to get that last 1k rpm? 15,17?
Spark is jumping 7/16 gap. Compression is 130,130,122 bottom. New plugs.
Should this be moved to Yamaha motor forum? Or could it still be a prop issue?
I have not yet weighed the boat... when I first got it a year ago, I took everything out/off and repainted the inside. With the boat completely stripped, I was able to pick the back of it up off the trailer and adjust how it rode on trailer. Im a small guy and 850lbs is a lot of weight.
Also did not do cylinder drop test as suggested. Is this something the dealer would have checked? Shall I still do it? Mild load as in 3 mph? Or 10 mph? At what rpm?
Thanks for all the help and suggestions so far... I just know this is going to end up being something simple. I am just not an outboard mechanic and don't know what to look for.
 
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danjb

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Feb 10, 2014
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I also read through dingbat's linked thread again... They were getting top speeds of 23 to 25 to 27mph. I'm fine with that, but they're also getting 5400 rpms. Unless this model tunnel just planes differently, I doesn't feel or ride like any other boat I've been on.
 

Faztbullet

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Take your prop and have it double cupped it will make prop bite better and ventilate less at positive trim.
 

Watermann

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Should I go up in prop pitch to get that last 1k rpm? 15,17?

That's the wrong direction, you have to go down in prop pitch to gain RPMs. Rule of thumb is 200 RPMs for each inch of pitch + or -
 

Sea Rider

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You have to check engine tech specs to know if engine wot revs safely between :

5000-6000
5500-6000
or even up to 6300 wot rpm.

Then can play with prop pitches all you want as loaded, load is a rpm serial killer when selecting +,- pitches.

Happy Boating
 

Scott Danforth

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And yes, a test tank runs a test prop to load the motor
 

danjb

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The manual says 4500-5500 rpms at full throttle. So I'm guessing that that's it! Nothing wrong with motor or prop, maybe go back down to a factory 3 blade 13p aluminum prop to get to the lowest normal operating rpm at WOT. I may be chasing ghosts. Will still tinker with fuel feed, already bought the stuff. Still doesn't feel right though... and they did say they got the 5500rpms in the test tank. If motor is loaded up in the tank, what's changing from there to the lake?
 

Sea Rider

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If preferred prop it right with a 3 blade alum prop for OB to run towards max 5500 wot range as loaded. That way will have better hole shot. with a prop that achieves 5000 wot revs will only achieve slight more top end speed but sacrificing best hole shot which is preferred. Besides nobody runs full throttle all the time..

Is not same an engine revving full wot revs with a test prop on a barrel than doing same with a "physical load" while combo runs on water at speed. Both are different scenarios. I'm sure will not rev same at full grip.

Happy Boating
 
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