1989 Evinrude 175 won't plane off

[MaryS]

We just installed a 4 blade prop, not sure of the pitch and not sure if this has anything to do with the current problem, but the motor is extremely sluggish when we try to plane off.

We cleaned the fuel filter and replaced the plugs but after reading a recent thread in here about prop pitch, and similar issues...could the prop be the problem?

It really just acts like its not getting enough fuel.

My boyfriend insists on taking this into someone and so far has been told this could be a $600 repair. They are saying that the carbuerators need to be rebuilt. I'm not sure how they can make that determination without seeing the boat which has me questioning their diagnoses.

I am trying to research this a bit further in order to determine the real cause before we take it anywhere.

Any help you can give would be greatly appreciated. I will try my best to give you the information you need in order to help me.

 

[modsrx]

Re: 1989 Evinrude 175 won't plane off

well we need to know the pitch and the size of the boat to start somewhere.... something close to 21 pitch on a 18-21 feet should work great ...make sure all plug have good spark at leat one plug on eatch side to make sure the stator and the other electronic stuff works ok

 

[jtexas]

Re: 1989 Evinrude 175 won't plane off

performance change was concurrent with the prop change? What other recent changes have you made to the boat? What maintenance has been done on the motor?
What problem were you trying to solve by changing props?
What's your WOT RPM's, before & after the prop change?
What's the diameter & pitch of the old prop & new prop?
Can you put the old prop back on & see if the problem goes away?

Put it in a shop, $600 is just the price of admission..........

Does the fuel line hold pressure?
Fresh gas?
Water in fuel?
Clean tank?
Tank vent clear?
Built-in or portable tank?
All fuel lines in good condition?
VRO still connected, or pre-mix?
Compression?

 

[MaryS]

Re: 1989 Evinrude 175 won't plane off

I would say that, although not immediately, the performance change occurred not long after the prop change. My boyfriend replaced the 3 blade prop with a 4 blade prop because he hit concrete with the 3 bladed prop and had heard such great things about the 4 bladed props.

The fuel line is holding pressure and there is fresh gas in the tank (portable). The other questions I will have to get with him to answer.

I do appreciate all the help and wish I was able to answer more of the questions.

 

[LadyFish]

Re: 1989 Evinrude 175 won't plane off

He'll get an earfull tonight! HAHAHAHA

Hi guys, Mary is a coworker of mine and I turned her on to this site and ya'll for advice.

I hate to see people get taken advantage of and spend hundreds of dollars when it could be something very simple.

Thank you for helping her out. I know she will find out what you need to know tonight.

Y'all are awesome!

TY

 

[jtexas]

Re: 1989 Evinrude 175 won't plane off

a prop change makes an immediate, not a gradual change.

your symptoms do sound like its time for a carb rebuild - $600 ought to be about right for three 2-barrel carbs. Any competent shop will do some tests to rule out compression or spark issues before starting. If y'all are the least bit mechanical-minded, you could get the parts on iboats for about $25 plus a couple cans of carb cleaner, and spend an afternoon getting to know your engine..........

 

[MaryS]

Re: 1989 Evinrude 175 won't plane off

Okay, I was able to get additional information. The WOT RPM's before the prop change was approximately 5500 and after the prop change was 4500. The diameter of the old prop was 14.5 (24 pitch) and the new 13 3/4 (23 pitch). I was mistaken about the tank, it is a built in tank. The VRO is no longer connected.

I believe I have answered all of the questions that were asked. Should additional information be helpful, please let me know. Thanks again for all of your help.

 

[jtexas]

Re: 1989 Evinrude 175 won't plane off

you'd expect better hole shot and higher top end RPM's with that new prop - I said $25 in parts before, but should of been $36 (3 kits at $12). Were it mine, I'd do a compression test & spark test as described here:

(General Engine Checks)
(J. Reeves)

First, check the compression. It should be approx 100+ psi and even on all cylinders.

Next, with the s/plugs removed, check the spark. It should jump a 7/16" gap with a strong blue flame on all cylinders. (The s/plugs must be removed in order to obtain the highest rpm available).

if those check out, I'd rebuild the carbs.

good luck!

 

[walleyehed]

Re: 1989 Evinrude 175 won't plane off

I would also likely be looking at the carbs....the prop change, even though 2 different designs can throw the rules out the window, (we don't know what make and model each prop "is") we can expect "about" the same RPM when dropping an inch in pitch and adding another blade.
I have a very simular engine and a question I have (beings you are pre-mixing oil) is how much time do the current plugs have on them? If they've been in for a year, replace them with the correct champion plugs.
On a 6 cylinder, if you lose 1 plug (fouled), you just lost about 17% of the power out-put, AND added about another 10% loss due to the drag of the components in the non-firing cylinder. Not saying the carbs don't need service-they may indeed-The spark-check would be the first place I would look and put new plugs in if they weren't changed for this season.

 

[mokaction]

Re: 1989 Evinrude 175 won't plane off

Go back to old prop.. Also check compress and do a spark test, could be one cyclinder is not firing. Also stick with the old prop cause it was what the old johnson liked. You can get them cheap on ebay or go to westmarine.


Larry