Loss of power underway after overheat

[ziptdodah]

Hello all!

I'm a new member here so please be patient with my post.

I have an 1989 Sea Ray BR200, 4.3LX with a Gen I Mercruiser outdrive. I recently had an overheat condition at low speed. She got hot enought to sound the alarm.
I put her in neutral and increased the water flow and brought the temp back down.

On the way back to the ramp I was having a problem staying on plane at a normal 3-3500 rpm.

I have since replaced the failed impeller (only 1 season old), replaced the prop with a new one and did the annual fluid changes, and drained the fuel tank for good measure.

On my checkout run this weekend, temp problem is fixed, but I seem to be having the same problem of speed. I can plane up okay out of the hole but at cruise the aft drops. It seems to be cavitating maybe? Trim seems to be working okay.

Would a damaged exhaust bellow cause enough gas to be introduced in front of the prop? What else do you think I broke?

 

[Big Billy]

Check the spark advance on your distributor. Check the timing on the engine and whle you're pulling the trigger on the light, speed the engine up and see if the spark advances. If it stays put, you need a new advance mechanism...

Bill

 

[ziptdodah]

Do you think it is related to the overheat? Prob started just afterward and continues.

 

[Big Billy]

Not especially...it's an easy check...if the distributor is original, all the little springs and weights can corrode in one place...thus causing your problem.....other suspicious things are plug wires and coil that tend to break down under strain...may not be related to overheating at all....

 

[ziptdodah]

Thanks, I'll check it out this weekend. I think something else is going on maybe.

Exhaust resriction maybe. Don't know. I guess we will find out

 

[Big Billy]

I know it's a tough one, try the easy stuff first. The fact that it gets on plane and then looses speed, could be so many things fuel, compression, etc.....

 

[Lauralex]

Was the propeller you replaced the same pitch as the old one?

 

[ShamuToo]

No springs or weights inside an 89 model mercruiser. All the advance is handled by the electronic ignition module mounted on the side of the exhaust elbow. Only the initial advance is adjustable.

 

[ziptdodah]

Prop was the same pitch. I'm thinking exhaust blockage?