1993 70HP Rude, vro disco'd.. believe to be in slow mode

[jvaccarino]

Good evening...

I have had some problems with this engine in the past, and seems to always go back in "slow" mode...

The first time it needed new carbs, second was the temp sense.. 2 weeks ago.. I thought it was the cabs again, but turned out to be the gas tank vent..

SO, 2 weeks ago, out on the water.. vent closed.. boat moved slow.. opened the vent.. boat started to move again(after a few minutes).. week later, got into some muddy water at boat ramp, then BAM, won't rev past 3000..

Carbs are getting gas, **** coming out of engine is between 70 and 80 degrees,..

Alarm has not sounded for overheat, I have not disco'd the Tstat yet (btw where is it???!) Also, the impeller has not been replaced (at least for the 3 years I have owned the boat).. Spark plugs could use replacing, but are less than a year old.

I want to know what I can do to stop this from happening every year! How much effect does the Impeller have on slow mode?

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

To view a diagram of your outboard(ie locate the t stats), visit www.shop.evinrude.com, then follow the links to your particular model.

The impeller is a critical piece of the coolng system, cheap part but its failure is catastrophic. If it has been 3 years, you are due. Change it out, inspect the water pump for damage as change as needed, and change the t stats while you are at it. This will allow you to flush the cooling system while the lu is down. Run the garden hose or compressed air up the water line to the t stat housing, then backflush it from the t stat housing down to the water line. Clean out the intake area.

When the outboard is limited to 2500 RPM, use a temperature probe or a infrared thermometer and verify that the engine is not overheating. Disconnect the tan temperature wire from the pack and retest. If the engine now performs properly, replace the temperature switch. Make sure the tan temperature switch wire is not located next to a spark plug wire.

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Is the thermostat going to be located in the cylinder head? If I disco' the tan wire, will I hear an alarm sound? Or would I have to touch the wire to the motor or something to ground it out, to hear a sound? What temperature should the motor be running at to not be "overheated?"

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Is the tstat aka the "temperature switch?" also comes out of the cylinder head.. The "temp switch" on the evinrude site has wire leads coming from it, the "thermostat" just sits inside the head.

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Correct about the t stat, located here, #37 in the diagram.

http://shop2.evinrude.com/ext/index.aspx?s1=fc6d2f0fe2248cf35a6520042a43ebc0


You would have to ground the tan wire to test the overheat alarm, to ensure that it is functioning.

Your t stats probably open at around 145 F, allowing the heated water to pass through the discharge. The temp switch will close at a temp of 211 F, and re open when it gets down to 175 F

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

No the t stat and temp switch have different roles.

That motor has a recirculating cooling system where the water pump supplies water to the powerhead through the "up" tube. The water circulates in the powerhead and absorbs heat, then is presented to the thermostat. If the 'stat says it is warm enough, it opens and the water is discharged and replaced with cool water from the pump.

Heat switches, installed in each cylinder head, are in series with a "HOT" warning horn in the remote control box. Should an irregularity develop in the cooling system and cause abnormal water jacket temperatures, the switches close the warning circuit. These are tested by submerging in hot oil with a thermometer.

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Ok, grounding out the temp switch just says that the alarm is working by completing the circuit. By disconnecting the Tan wire, and running the engine and it surpasses 2500 rpm I will know if the the switch is bad.

Lets say I don't get an alarm, disco the wire anyway, run the engine, and it is still in slow mode.. Am I know looking at a fuel problem now?

Do I have to have resistance on the prop to test this, or can I put the muffs on in my driveway?

 

[clanton]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

The temp switch wire should be tan/blue stripe. What is the model and serial number of the engine.

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Correct, you got it.

You do not need to be on the water (under load) for this testing. Grounding out the tan wire should produce an audible horn. I would also imagine on that model the horn should sound when the key is engaged, if it is not functioning, it should be reparied before running. If in fact the horn functions properly, and you are not overheating, you may not be in SLOW mode at all, you may be dropping a cylinder. The horn should sound for a fuel restriction as well, unless of course it is not functioning, this is why you need to determine if it is functioning properly.

If the horn is functioning, and you are not overheating and you do not have a fuel restriction,
do a compression and spark test, ensuring the spark jumps a 7/16 of an inch gap with a bright blue ZAP!! and the compression is around 100 psi and even on all cylinders.

 

[ezeke]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

edit

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

model is VE70TLETS

serial - Q03205806

White and blue and tan and blue wires coming from the temp switch..

which side of the switch needs to be grounded for the alarm to sound?

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

That is just about the worst way to test an overheat alarm that I have ever heard of.

Will we be getting an elaboration on such an omniscient statement?

 

[ezeke]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

edit​

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

admiral... is that the wrong approach in determining the sensor being bad? I understand to use a thermostat in reading the temperature and then to disco the sensor to determine if it is the sensor or not...

what other way is there??

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Excuse my rudeness Ezeke, I was under the impression that you were attacking my attempt to help him. I apologize, bad day at work. Not always correct, but I sure do try hard

JV, the best way to test the switch is by submerging it in hot oil with a thermometer and checking the temps at which it opens and closes.

Have you determined if your horn in fact works?

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

I am just gathering information tonight.. I will be working on the engine tomorrow nite.... which side of the therm. switch needs to be grounded out to test the horn?

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

You need to ground the tan wire only.

Just a thought, Im not positive on your model, but is there a small slot underneath the fast idle lever on your remote control? If there is, inserting a key or similar metal tool while in the 'on' position completes the horn circuit for an audible test.

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

Right I know the tan wire.. but from the power pack or from the switch side? I would assume the power pack side.

and I'm not sure what you are referring to about the 'remote control?'

also.. I am not able to pull apart the connection to the tstat switch of the tan wire.. I can pull the white wire apart with no problem.

From the power pack side, the connection to the tan wire is black inside.

 

[HighTrim]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

A remote control refers to the box to the right of the driver which has the key switch and throttle control. 'Tstat' is slang or short form for thermostat. Lazy typer!

 

[jvaccarino]

Re: 1993 70HP Rude, vro disco'd.. believe to be in slow mode

I don't see any small slots near my remote control ..so.. which side of the temperature switch am I supposed to be ground out?? PPack side?? And does the fact that I cannot take the connection apart and that it is black inside, have any indication about anything?