2001 evinrude 4 stroke wont run over 2900 rpms?

[tayter33]

when 1st start runs fine for 15 minutes then starts cutting out. will run at 2900 perfectly. any ideas of issue??

 

[seahorse5]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

How about a model number so we know what motor you are asking about?

 

[boobie]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

A model # and a little better description of what the prob is would be helpfull if you want any answers. Will it go over 2900 ?? And after that what happens ?? How do you know it's 2900 ??

 

[trendsetter240]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

Agreed with the above. Hard to help without knowing what motor we are talking about here!

Also, if you have a compression gauge, a compression test will help to identify the issue. If you are able to test the compression please post back the results along with the model number.

 

[tayter33]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

How about a model number so we know what motor you are asking about?

model E50PL4SI serial G18007570 - just bought a 1987 crest 10x35 wb pontoon houseboat and took out this weekend and everything ran good. as long as i stayed under 2900 rpms ( have guage). on return trip tried to trottle up over 2900 and motor was surging. called previous owner and he said was cavating??? i dont believe this to be the issue. he claims always ran that way over 2900 rpms.

 

[daselbee]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

Surging....OK I will take it exactly like you describe it.
The Ev/Suz 4 strokes have a rev limiter that kicks in when the engine overheats. There are two temp sensors on the engine, one in the side of the block to the top/rear of the plastic EMM holder (behind it kind of), and the other in the exhaust manifold (you can see it clearly).
You cannot disconnect them to test like you might with a EV/John because the EMM is constantly monitoring the voltage across them, and translating that voltage to temperature.
I would look first at the overall temp of the engine with a temp gun. Top of thermostat housing should be at 145 degrees. Down by the sides of each plug should be about 165 degrees, with #4 being a bit lower. Why? Dunno. They are like that.
The SUZ service manual is just about a requirement for testing these sensors. EV manual is OK, but the SUZ manual is much better.

The other typical thing that causes the surging you describe is if the neutral switch is malfunctioning. This switch islocated down below the oil filter on the throttle mechanism.
Example: Engine in neutral, but you have revved the engine up manually. The rev limiter will kick in and prevent over revving and surge violently. Major surging....

So, look at the proper operation of the neutral switch, also. I don't have my book here in front of me, so I cannot tell you if the switch is OPEN or CLOSED when in the neutral position. I will post that info later. But, it would be OK to just put a meter across the switch leads, and see if the meter responds when you operate the throttle from neutral into gear. If the meter responds, the switch is working.
I won't get into how to use a meter...gotta figure that out by yourself.

So, for example, if the switch has failed in the position that makes the EMM think the engine is ALWAYS in neutral, and you shift and go, when it gets up to the rev limit RPM, surging occurs.

One other thing....all these sensors and switches are very difficult to back probe. The connector for the neutral switch is buried behind the EMM, for example. Typical service for these engines is performed with a "breakout cable" that SUZ dealers have.


EDIT:
AWWW Crap.....I just re-read and see that you have a 50 horse. I was describing the location of those sensors and switches on a 70 horse.
Sorry if this confuses you, but the operation concepts are the same. Surging occurs with overheat or neutral switch malfunction. You will have to locate the switches/sensors on your motor, but they are there.

 

[daselbee]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

Where did this guy go? This is one of the most frustrating thing about these forums.
You go to the trouble to post, help someone, and dead silence. Not even a peep.

Anyway, I said I would post the switch position...when in neutral, the neutral switch is CLOSED.
When in FWD or REV, the switch opens up.

The resistance of the temp sensors at 75* F is 1.8k to 2.3k. The temp sensor reduces in resistance when the temp goes up.

The engine will also surge when the oil pressure is low.

Good luck.

 

[tayter33]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

Where did this guy go? This is one of the most frustrating thing about these forums.
You go to the trouble to post, help someone, and dead silence. Not even a peep.

Anyway, I said I would post the switch position...when in neutral, the neutral switch is CLOSED.
When in FWD or REV, the switch opens up.

The resistance of the temp sensors at 75* F is 1.8k to 2.3k. The temp sensor reduces in resistance when the temp goes up.

The engine will also surge when the oil pressure is low.

Good luck.

going to lake this weekend to try and see if that is the case. thanks for info, will update results monday

 

[daselbee]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

OK thanks. Please let us know what you find.

 

[WIMUSKY]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

Sounds like daselbee is all over it. I have the same EMM/S.L.O.W. system on my 60hp. Had it kick in when I went thru a weed patch. Tried to get on plane and it shook at 3000rpm. Removed the weeds from the water inlet and all was well. It's a good safety system....

 

[tayter33]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

checked motor different way, scanned both tempature sensors: 1 read 140 and the other at 138 with cover off at 2900 rpms. run motor with cover off upto 3600 rpms and did fine. put cover back on and trip sensor at 3000 rpms. would this be a temp sensor issue because the motor is not runnin hot?????

 

[daselbee]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

OK...so you read the temps with a gun...OK....so all you know is that the gun says it is not overheating.
But what does the EMM think? It knows nothing about the gun. All it knows is the voltages it sees from the temp sensors.

Don't get me wrong.....it is great that you verified with the gun that it was not overheating. So the next logical thing to look at is the possibility that one of the temp sensors is malfunctioning, and telling the EMM it is hot when it really isn't.

You cannot assume anything until you do all the testing. Remember, these temp sensors are not simple switches like J/E temp sensors. They change resistance with a change in temperature. Also, you cannot just disconnect them to test.

You need to read the codes from your EMM at the tach. Your tach should be blinking codes at you.
You also need the FACTORY service manual. I would get the Suzuki manual. It is a bit more detailed.
I don't have the 50hp manual....just the 70, so anything I post here detail-wise will not exactly match your engine.

 

[tayter33]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

OK...so you read the temps with a gun...OK....so all you know is that the gun says it is not overheating.
But what does the EMM think? It knows nothing about the gun. All it knows is the voltages it sees from the temp sensors.

Don't get me wrong.....it is great that you verified with the gun that it was not overheating. So the next logical thing to look at is the possibility that one of the temp sensors is malfunctioning, and telling the EMM it is hot when it really isn't.

You cannot assume anything until you do all the testing. Remember, these temp sensors are not simple switches like J/E temp sensors. They change resistance with a change in temperature. Also, you cannot just disconnect them to test.

You need to read the codes from your EMM at the tach. Your tach should be blinking codes at you.
You also need the FACTORY service manual. I would get the Suzuki manual. It is a bit more detailed.
I don't have the 50hp manual....just the 70, so anything I post here detail-wise will not exactly match your engine.

new motor on old boat, dont have tach whats EMM?

 

[daselbee]

Re: 2001 evinrude 4 stroke wont run over 2900 rpms?

EMM Engine Management Module. The computer that runs it.

You are guessing without the codes available to you, if it is throwing codes.

 

[ignorant]

I realize this is an old thread, but I did not see where the issue had been resolved. I have the same Evinrude with the same issue. model E50PL4SI, serial # 18008304

Idles fine but when RPM reach 2900 it begins surging and will not go above that point.
I am in the process of trying to buy a service manual as suggested.
I have worked on lots of equipment, but 4 stroke boat motors are completely foreign to me. I will my best to follow any instructions and report results but please be patient.
I read it could very well be temperature related. My motor has no "tailtell" water discharge. There is a rubber plug in the rear and if I remove it water will flow out but it is like an old man at the urinal, not the strong stream that young men and normal motors have. Should that plug be left in or should it be out?

any and all help will be appreciated.

 

[tpenfield]

I realize this is an old thread, but I did not see where the issue had been resolved.

Some threads go that way, but not a reason to post to a a 10 year old thread. Please review the rule about posting to old threads and feel free to start a new thread with your relevant information.