1990 Evinrude 40hp will not reach max RPM at WOT

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lakeyar

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Hi. We have a Tracker 17' with a 40hp evinrude dual carb. I have read elsewhere in the forums that the max rpm at WOT is ~6000. As of now the highest it will get is ~4300. We adjusted the throttle linkage and the when the throttle is at WOT the carbs are wide open. When on the lake if we put the throttle at WOT the engine seems to bog down, but if we back it off a little (inch or two) it will take off and wind up to ~4300, but even after that if taken to WOT it loses power. We adjusted the spark advance slightly and it didnt seem to make any noticeable difference. If anyone has any good ideas on how we can get this engine to run at ~6000 it would be greatly appreciated.

Thanks in advance. Adam L.
 

petryshyn

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Could be fuel starvation or ignition system breaking down. Don't operate the unit until its rectified or major engine damage could occur.

-have you tried running it with a loosened gas cap?
-does it help to firm up the primer bulb when it bogs?
-do you have another set of plugs to try?
 

countvlad

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Hi. We have a Tracker 17' with a 40hp evinrude dual carb. I have read elsewhere in the forums that the max rpm at WOT is ~6000. As of now the highest it will get is ~4300. We adjusted the throttle linkage and the when the throttle is at WOT the carbs are wide open. When on the lake if we put the throttle at WOT the engine seems to bog down, but if we back it off a little (inch or two) it will take off and wind up to ~4300, but even after that if taken to WOT it loses power. We adjusted the spark advance slightly and it didnt seem to make any noticeable difference. If anyone has any good ideas on how we can get this engine to run at ~6000 it would be greatly appreciated.

Thanks in advance. Adam L.

you might be too advanced... its possible when you let off the throttle you bring the timing back/down and thats why its catching up... make sure your timing is right.... do a decarb
 

lakeyar

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Will give those a try next time we take it out. It definitely acts like it is either starving for fuel or air though. Thanks for the advice and will let you know if it leads us to a solution :)
 

northernmerc

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Maybe you need to change the prop to a different pitch prop. In the past, could this motor on this boat reach 6000 rpm? If the answer is yes, you likely have a problem with the motor. If you don't know, try changing the prop.

Also, a 40 hp sounds rather small for a 17 foot Tracker, at least for the 17 foot trackers that I have known.
 

lakeyar

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Maybe you need to change the prop to a different pitch prop. In the past, could this motor on this boat reach 6000 rpm? If the answer is yes, you likely have a problem with the motor. If you don't know, try changing the prop.

Also, a 40 hp sounds rather small for a 17 foot Tracker, at least for the 17 foot trackers that I have known.

We havent had the boat for very long but it is the engine (and prop we're assuming) that came on the boat. It doesnt seem to be a running out of power thing, more of a starvation or some other problem tho.
 

kenmyfam

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

We havent had the boat for very long but it is the engine (and prop we're assuming) that came on the boat. It doesnt seem to be a running out of power thing, more of a starvation or some other problem tho.
I think the question was "Did it ever reach the desired RPM ?? "
 

lakeyar

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

I think the question was "Did it ever reach the desired RPM ?? "

Oh ya. Sorry, I must have started typing and got off track. It has never reached it for us. The previous owner said it didnt for him. As for the original owner, no idea.
 

Randybeall

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Oh ya. Sorry, I must have started typing and got off track. It has never reached it for us. The previous owner said it didnt for him. As for the original owner, no idea.

Sounds like a job for the prop forum. What prop do you have now? Go to the prop forum, read the sticky which gives you the list of information needed and we can most likely come up with a good answer, even if it turns out you have the right prop now. Your description sounds like an over propped engine.
 

kenmyfam

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Needs a basic health check to begin with,
Compression, Spark, fuel delivery, plug condition, possible decarb and post results. Go from there. Link'n sync would certainly not hurt either.
 

countvlad

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Sounds like a job for the prop forum. What prop do you have now? Go to the prop forum, read the sticky which gives you the list of information needed and we can most likely come up with a good answer, even if it turns out you have the right prop now. Your description sounds like an over propped engine.

i agree... now that i read more i realized that you have never reached the manufct WOT range.....

if the previous owner never reached the desired RPMs i would get a diffrent prop... but before gettinga diffrent prop ake sure theres nothing wrong with the motor.. eg do a decarb, check timing, make sure you have the right sparkplugs, etc....

lets say all these were done then get a diffrent prop... every drop in pitch its aprox 200 RPMS gain.... find out what the recomended manufct WOT range is and try to stay in 25% top range...

whats the prop pitch on the boat right now.??? seems like you might have to drop at least 7 pitch from the actual prop.. andif i were you i wouldnt run that boat until i get it fixed.... too hard on the motor...
 

lakeyar

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Well. I guess that the prop idea COULD be the problem. But when running at the max now (4300) the engine doesnt act like it is straining or anything, its running like a champ. When the throttle is put all the way to WOT it actually drops way down in rpm, substantially below 4300 (like you let off on the throttle), it doesnt even "try" to wind up anymore. Ill check the prop pitch as soon as I can and post it though.
 

kenmyfam

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

I still say start with a basic health check. What size prop is on it now ???
 

lakeyar

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Well, I think we are making some progress. Found out that the throttle was adjusted wrong, so it was going past WOT and restricting again. Fixed that. Also found that the roller cam bushing for the spark advance lever was broken and gone, got a new one but havent tested it out yet.

For the people asking the prop size its a 1 3/4 x 17
 

jonnyv

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Re: 1990 Evinrude 40hp will not reach max RPM at WOT

Well, I think we are making some progress. Found out that the throttle was adjusted wrong, so it was going past WOT and restricting again. Fixed that. Also found that the roller cam bushing for the spark advance lever was broken and gone, got a new one but havent tested it out yet.

For the people asking the prop size its a 1 3/4 x 17

Seems like everyone has the same problem with this vintage vro...
i am in the same boat I can only get 1/3 throttle
 

Skipw

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I have a 1992 bass tracker tx17 with a 40hp tracker evinrude and right now I get 47mph with a 11 3/4 ×17 pro comp prop. It's all in the height of the motor . A hydronic trim and tilt helps. At wot you can achieve over 50mph at 5900rpm if you set your motor to the highest level without cavitation. Bass boats in general, like most boats, are not rigged for optimum speed, just general usage. They are mounted too low and cause lower unit drag. The cavitation plate height on my boat is 1 1/2 inches above the keel.
 

GA_Boater

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Quoted for truth. Nothing like a nine year old thread resurrection too. Happy Xmas.

That's why the poster got coal in his stocking. :lol:

Skipw Please look at the rules about posting in old threads. Thanks.

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