1995 Evinrude 150 slow mode??

[danno0676]

I have a 1995 wahoo 21 with a 1995 evinrude 150 ocean pro that I think is entering slow mode. I bought the boat about a month and a half ago, it ran excellent on sea trails except for a VRO alarm that I used for my advantage when coming to a final price. So I bought it, disabled the VRO, plugged the oil suction line, disconnected the 2 wires going to the VRO tank and unplugged the 4 wire connector at the pump. After that it set for a month while I was away for work (tug boat).

When i returned home I replaced the fuel lines from the tank to the engine, installed a new primer bulb, and a Yamaha fuel/water separator and pumped all 50 gallons of ethanol free gas out, through the filters, then poured it back in and pumped it out again. Now it's nice and clean, i mixed the fuel 50:1 with BRP 50 oil and poured it in the tank and installed a new filter.

Time to have fun, test started it on the trailer and ran great. In the water it bogged and ran very poor under load. Found a stuck float. I removed the one carb, freed the float, runs great under load BUT
1 when you reach ~4200rpm it enters slow
2 idle to wo throttle (quick "stab/punch" of the throttle)it immediately enters slow
3 slowly creep to 4200, runs fine, then slow
It will stay in slow until I put it in neutral and rev with no load on it, then any of the above will put it back in slow.
While trying to diagnose I installed new, properly gapped, champion plugs and a new engine fuel filter. I removed, then head temp sensors same thing, unplugged the temp sensors, same thing. I also tried a small gas can connector directly to the engine with the old primer bulb and fuel line to eliminate the fuel pick upon the boat's tank as well as the filter set up I had installed.

Any more bright ideas??

Thanks!!

 

[flyingscott]

S.L.O.W happens around 2500-2800 rpm. Does that have the optical ignition? Have you done a compression test? Did you do a spark test?

 

[Chris1956]

If you disconnected the heat sensors and she still went into SLOW, the fault is likely with the wiring. There is a diode in the wiring harness to isolate the overheat from other alarms. You might check it.

Also check the shift assist switch as that will kill spark to 1/2 the engine.

You are sure she is not overheating?

 

[flyingscott]

The Diode isolates the VRO alarm from the rest of the system. If that was happening S.L.O.W would kick in at 2500-2800 rpm.

 

[danno0676]

When it enters slow, if that is what is happening, the engine will drop to around 2200 ish, tach is a but hard to read because the gauge is milky in that area.
I removed the 2 wire heat sensor and unplugged the 1 wire heat sensor. That would eliminate and overheat signal if the engine were actually overheating, but would not eliminate a wiring issue.
I did a compression test with all plugs out before purchasing, they were all close, I believe around 120.

It does have optical ignition. I have not done a spark test because from what I have read I need a special tool that I do not have.

There is a lot of water coming from the tell tale, as much as that means.

Like I said, it ran great on several sea trials of 5-10 minutes each at wot around 5500 rpm. This scenario happens within the first few minutes of running and only above 4200 rpm or wot, but then is able to be "reset" with a neutral rev.

I know the alarm speaker works as I get the chirp when the key is turned to on. I have tried choking it with the key and pumping the primer with no luck.

Later I am going to try and unplug the 2 wire sensor and see what happens. It was too dark when I tried removing them to stay out any longer.

I took a video but unfortunately there is too much wind noise to hear what is going on.

 

[flyingscott]

That sounds more like a fuel issue. LIke you have a carb loading up or bad plug. No special tool needed to check spark $10 spark checker is all. Spark needs to jump a 7/16" gap.

 

[danno0676]

Kind of what I'm thinking too, fuel. Something about the position of the throttle.

 

[danno0676]

To add some more, I unplugged both temp sensors and there was nonl change.

I was able to see the tach better today, the rpm it does its thing at is around 4500, which no ow that I think about it is more like where it was bbn on the sea trails prior to purchasing. Once whatever happens happens the rpms will not exceed 3000 and it is very slow to rev there.

Engine runs smoothly, just won't go past that rpm.

 

[flyingscott]

Get a manual and start checking the electronics on it.

 

[danno0676]

Well I figured it out. I'll post some info later, but it was very weird!!!

 

[danno0676]

Ok, first forgive me for not knowing the proper terminology for what I am about to describe.
On the top of the engine where the timing adjustments are, and I assume where the optical sensor is, there is a metal rod that connects it to a plastic cam that operates the carb linkage, well on the cam side for the carb linkage it had broken in the past and someone had zip tied it together. There would be just enough pressure at a certain throttle input to allow the metal rod to slip inside of the cam, allowing the throttle linkage to reset itself. When I would rev the engine in neutral the movement of everything would allow the metal rod to get reseated in the cam.

Weird enough for you?

Thanks everyone for your inputs!!

 

[danno0676]

[No message]

 

[Chris1956]

You did not think a zip tie on the throttle linkage was out of place? I would recommend you look that motor over some more, in case there is some other special modifications.

 

[FreeBeeTony]

I had a similar issue w/ twin 175's I purchased a few months ago!
The same piece (cam) was broken on the port engine and held together with a hose clamp!
I didn't notice it until I brought the boat home........
Ordered a new cam and replaced!

 

[danno0676]

No, I didn't notice a 1/16" black zip tie being out of place, neither did the 30 year marine mechanic. It was very sneakily installed an almost invisible.

 

[danno0676]

I had a similar issue w/ twin 175's I purchased a few months ago!
The same piece (cam) was broken on the port engine and held together with a hose clamp!
I didn't notice it until I brought the boat home........
Ordered a new cam and replaced!

Nice to hear I'm not the only one!!

Mine is all fixed up now an we have been enjoying it today.