88 Mercury Black Max 150 XR4 Beeping and Cutting Out Need Help

"Hello all. For the past sever

"Hello all. For the past several months, I've been restoring a 1985 Charger Foxfire with a 1988 Mercury 150 XR4 on it. I finally had a chance to get it out on the water today (for the first time), and ran into some problems. I have done the following to this motor to date:

• Replaced water pump.
• Rebuilt fuel pump.
• Replaced the oil lines.
• Replaced 1 switch box.
• Drained and replaced lower unit oil.

When I got her out on the water, I ran into some trouble. The motor starts fine, and idles beautifully. The boat comes out of the hole quickly, and rides great. The problem begins when I get her going past about 1/4 throttle. Once on plane, and at about 1/4 throttle, it runs perfectly and purrs like a kitten.

Once I push it to about 1/2 throttle, the throttle control/housing starts intermittently beeping beep - beep - beeeeep - beep, and the motor begins to run rough. There is no pattern to the beeping, but it doesn't stop. The motor itself stops running smoothly at about 1/2 throttle, and the prop in the water starts to make a "garble" sound, like the prop is not running in clean water. The further I push the throttle, the higher the RPM's go, but the boat does not pick-up any speed. It just runs really rough, and won't go any faster.

I tried giving it gas around a corner to see if cavitation was the problem, but it didn't change anything. I'm really at a loss as to what the problem might be. Can anyone out there help me figure this out? Thanks so much ac."

"Hi there!

Has the prop bee

"Hi there!

Has the prop been repaired before? Any signs of welding, grinding or fresh paint?

Sounds like a slipping prop-bush. Try testing in both forward and reverse gears, when gears engaged, try twisting the prop. Remember that the motor has 150 horses to get the prop slipping, you might not have that power in your hands... So it might seem that there is no apparent slippage.

Make sure that motor cannot be started accidently...

Not really worth re-bushing, it will happen again, anyway. New prop is good option...

Regards!

Benjamin."

But that doesn't explain t

But that doesn't explain the beeping does it?could be a coincidence and there is also a problem with the alarm module ?

"Hey there...

Sorry, blond

"Hey there...

Sorry, blond moment...

I know that sound, almost as if the buzzer has a it's leads being dragged across a battery's terminal. Had similar issue with my 1997 Mariner 115 Offshore. Motor cuts out in sych as the buzzer sounds... There is a thread elsewhere here about my problem. I've yet to do water test, it's almost winter here in South Africa now...

The YEL/BLK wire is the alarm trigger. The cut-out switch, low oil and temp alarm works thru this line. I'm not too familiar with your motor, but check under the hood where this wire goes.

On my motor, there is a controller unit for low oil and temp. This unit would short to ground and hence cut signal to coils: no spark and buzzing.

I'd check the ignition switch, oil level sender (blue wires) or overheat ClixOn switch (one tan wire, other side runs to ground). If you can, isolate (disconnect) the YEL/BLK wire under the hood from said unit.

If problem persists, check control box and ignition switch for irregularities.

Also try to isolate YEL/BLK wire from the coils or ignition system. In my case, my motor has CDM modules, hence a YEL/BLK wire to each coil "unit".

Is your motor AutoLube? How's the oil use from the tank? Maybe good idea to pre-mix some fuel when you test the cut out system... Make sure that the tell-tale (pisser) is flowing strongly too.

Hope this helps?

Happy boating!

Kind regards!

Benjamin."

"First of all, thanks to every

"First of all, thanks to everyone that is trying to help. I really appreciate it! I have posted this question on a few different forums that I frequent, and I wanted to share a short list of some of the suggestions. Here goes:

1. The beeping is probably an indication that your oil pump is failing.

2. The running rough sounds like you've spun the hub on your prop.

3. Never replace only one switch box. If one was malfunctioning, it could have cross fired and perhaps damaged the other. Sometimes those switch boxes work perfect at the lower rpm ranges but then start doing really strange stuff at higher rpms.

4. If one of the switch boxes is still malfunctioning it could fire a cylinder out of order and detonate a piston.

5. The high speed side of your stator could be shot.

6. Sounds like a slipping prop-bush.

7. I'd check the ignition switch, oil level sender (blue wires) or overheat ClixOn switch (one tan wire, other side runs to ground). If you can, isolate (disconnect) the YEL/BLK wire under the hood from said unit. If problem persists, check control box and ignition switch for irregularities.

8. A sticky thermostat.

9. A bad oil injection sensor.

10. Check the Thermostat and Pittot Valves.

11.You have an overheating problem.

So this is the list that I have to work from so far this weekend. Is there anything here that I can knock-out quickly? Is there anything here that is obviosly incorrect? Let me know what you guys think about the solutions."

"OK - I took the prop off, and

"OK - I took the prop off, and it doesn't look like anything has been spun, unless I am missing something. I have posted some pics of the prop here:

http://www.flickr.com/photos/24479981@N03/

As for the beeping, I have a new oil sending unit. I am going to replace over the weekend, and see if that helps.

One other thing, when I left the cap off of the reserve tank on the front of the motor, I accidentally forgot to close it back before running it again. It lost some oil, but not much. I looked at that tank again tonight. It is full, but not to the brim. Maybe if I fill it all the way up, that will alleviate the alarm.

I am leaning toward the stator being bad as the cause of the poor performance past 1/4 throttle. I think that might be the problem. I would sure hate to drop $200 on a stator if it's not the real problem, though.

Any other advice out there would be greatly appreciated. AC"