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2000 150 Optimax sudden throttle/power loss

M

mdc4488

New member
2000 150 Optimax sudden throttle/power loss

I was on the river running 3/4 to full thrttl when the throttle suddenly went to idle, it did not stall. I shut it off and started right up but no throttle, would engage forward but there is no throttle or acceleration.
fuel or oil pump fuse? (not checked yet) or could this be the throttle sensor?

I would also like to know of the location of the "screen" in the water coolant line. Apparently this can get clogged affecting the water pressure of the coolant thru the motor.
quote from another thread "The technician took a harder look and found a clogged screen under the cowl. It definitely seemed to solve the (water flow) problem"

Thanks for any advise, Mike
 
Docksidemarineservices said:
First you should check your cable operation if you don't have smart-craft controls.
Click to expand...

1999 150 Optimax
After taking another look and having someone actuate the controls (cable) for shift and throttle I found the problem. The linkage for throttle at the intake had actually become disconnected! There is*no lock ring or*keeper on this connection.*In any case, an easy fix. *I also put a small nylon zip strap across the arm to keep it from popping off again (non-binding). You wouldn't want that strap to restrict the motion of the accelerator lever. A compression cap or some kind of clip on the end would also work. There should be no real force on this, it would be just to retain position in the lever fitting or holder.

Thanks Dockside for your replies.
 
Docksidemarineservices said:
First you should check your cable operation if you don't have smart-craft controls.
Click to expand...

I would also like to know of the location of the "screen" in the water coolant line. Apparently this can get clogged affecting the water pressure of the coolant thru the motor.
quote from another thread "The technician took a harder look and found a clogged screen under the cowl. It definitely seemed to solve the (water flow) problem"

It's actually a 1999 150 Merc Opti

Any ideas where on the motor this screen in the coolant line would be?
 
Mercruiserparts.com--------Seems to show a " strainer " on the page for waterhoses.----Item #8 on the page I looked at.
 
Yes, Merc calls it a "strainer".

Water passing through the strainer cools the compressor and then exits the tell tale (pee stream, pisser - whatever you want to call it).

It DOES NOT either affect the cooling of the powerhead itself, nor is indicative of the heads actually getting any cooling water. This is, in my opinion, one of the drawbacks of the cooling system on the early Opti's.

A weak tell tale could mean 1) you have a clogged strainer which means the compressor could potentially overheat.

2) your waterpump is on the way out and the whole motor is in danger of overheat.

What it DOES NOT tell you.

It doesn't tell you if water is getting to the heat exchanger on the return line for the fuel rails (an overheat here could cause an explosion in extreme cases)

It doesn't tell you if water is getting to the powerhead, the exhaust manifold or the heads themself - the feed for the tell tale (via the compressor) is at the front base of the exhaust plate where the water tube connects so any restriction on the (powerhead branch of the cooling system) would not be (detected/visable) at the tell tale - which could result in welded pistons etc.

However, a strong tell tale usually means that despite problems which may exist in the powerhead itself, including bad thermostats or poppets; your waterpump is probably fine.

These motors really "need" Smartcraft gauges to do the monitoring for you. They are not a traditional 2 stroke and they operate nothing like one. And even the tell tale, is not really much of a tell tale...
 
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