Loud buzzing sound on a 1988 Spectrum Bluefin Sportsman 1900 w/ a 85hp Force

[Dustin099]

Hey everyone, I'm new to boat ownership and a first time poster in here. I just bought the boat a couple days ago after a test ride with the previous owner.

When I took it out for the first time alone yesterday she started up just fine (after a few cranks) and ran great for the whole ride. After about an hour of crusing around at different speeds we dropped the boat down to just a little faster than idle speed for about 15 to 20 minutes. I heard a sudden buzz that lasted for maybe 2 seconds and went away. A few minutes later I went WOT (about 33 mph) on it and the buzzing started again and lasted for about 30 seconds untill I slowed down to an idle. We were out for about 30 minutes after that without anymore buzzing or problems.

According to the owners manual on the engine the buzzing was a alarm for overheating (above 180 degrees). I checked to make sure the engine was still peeing and it always was.

Should I be concerned? What can I do to prevent this from happening in the future and to avoid damage to my engine?

And ofcourse I would like to thank everyone in advance for sharing your knowledge and experience.

 

[pnwboat]

Re: Loud buzzing sound on a 1988 Spectrum Bluefin Sportsman 1900 w/ a 85hp Force

Yes you should be concerned. Overheating the engine can lead to a blown motor. First thing you should do is to perform a compression test. Ideally you should see 120LBS+ with all cylinders within 10% from lowest to highest reading. If that checks out, change the water pump impeller. Ther is a sticky at the top of this Forum regarding FAQ's. In that sticky, there is a step by step procedure to change the impeller.

 

[SweeperForce]

Re: Loud buzzing sound on a 1988 Spectrum Bluefin Sportsman 1900 w/ a 85hp Force

Welcome,
I have an 89 with the same overheat set up. My buzzer went off when my motor hit 85 degrees. So mine needs replaced. You can either buy a cheap infrared temp gun at Sears for about $30, buy a block temp gauge from iBoats, or use you hand. If you can touch the block for more than 2 seconds then your in no danger.
Another thought is your thermostat. Make sure it is opening up. Even though you are get water out of the relief port (peeing) no water is getting into the block. T-stats normally don't go bad, but for a few buck, might be a good idea to get a new one. To change it, remove the four screws of the square box sitting above the first spark plug. Take off the cover, remove the spring, and pull out the thermostat. Place the t-stat on a pot of boiling water and see if the stopper retracts. Heres a few photos, hope they help.


Tom

 

[Dustin099]

Re: Loud buzzing sound on a 1988 Spectrum Bluefin Sportsman 1900 w/ a 85hp Force

If I bought a infared temp gun where would I aim it at to get an accurate read of the temp?

 

[SweeperForce]

Re: Loud buzzing sound on a 1988 Spectrum Bluefin Sportsman 1900 w/ a 85hp Force

Right where the overheat sensor is located. Actually anywhere on the head or ehaust plate.