280 block teperature

[hastings]

Hello Guys,
I have a 2000 280 ROS.
Head Temp running 190 degrees at high speed. highest it's ever been. usually 170 degrees. Running 30 plus lbs. water pressure @ high speed.

The horn sounds when I turn the key on.

Two questions please before I do any damage. Can't afford to rebuild this year.

1) What should head temp be at maximum?

2) Is there a wire that I can ground to check the horn from the sensor.

3) Haven't replaced the pump kit this year but the water pressure is 30 lbs. at high speed so I figure she's good. Incorrect?

Regards
Doug

[Murry]

Sounds like you have a restriction with that much water pressure. The impeller may have broken and have pieces in the block or heads. Check the water pump first.

[hastings]

Hello Murry,
Thanks. Will do tomorrow. On the list.
Strange thing is I have always had 30 lbs. pressure with this 280 the 4 years that I have had it. Thought it was kinda high. Have sportmaster on it.
What are you running for max pressure and what set up?

Anybody else running 30 lbs with a sportmaster?

Regards
Doug

Sounds like you have a restriction with that much water pressure. The impeller may have broken and have pieces in the block or heads. Check the water pump first.

[Ted Stryker]

30 lbs. is too much if it is the factory exhaust adapter plate, I would think that it should be about 1/2 that as it is a high volume set-up with large dumps hole to move alot of water with low backpressure... Like Murry said, it seems there would be a restriction somehwere because 30 lbs. of free flowing water in a 280 would be a whole bunch of flow and unlikely to yeild such high temps... Check to see what size the I.D. is for the washers that are in place of where the T-stats go on other engines, 1/8" I.D. holes in the washers are pretty standard... I believe that engine should run about 110-120 degree fahrenheit water temp and the block will probabaly be around 140-150... Someone may chime in with more accuracy, but I think this is close...

[hastings]

Hello Murry and Ted,

Hold the fort.
Put in new impellor. Old one looked a bit worn but not bad and no rubber missing.

Borrowed temp sending unit from my buddy's motor and she is beauty.
Temp at 135 - 140 degrees flat out. Perfect.
Never ran this low.
Checked both head temps while hot with hand held laser gun. Both within a few degrees.
So the 30 lbs water pressure is still a mystery but we are good to go.

Thanks for the advice guys.

Regards
Doug

[Ranger976]

Sounds like you have a restriction with that much water pressure. The impeller may have broken and have pieces in the block or heads. Check the water pump first.

w/Murry....anytime you have high water pressure w/high head or water temp it usually points to some form of restriction....I'd pull the lower take a looksie at the impeller....if there's pieces missing I'd then pull the heads to look for pieces around the water jackets and keep searching till you prove to yourself that there's NOT a restriction.....just my .02

[Ted Stryker]

Hello Murry and Ted,

Hold the fort.
Put in new impellor. Old one looked a bit worn but not bad and no rubber missing.

Borrowed temp sending unit from my buddy's motor and she is beauty.
Temp at 135 - 140 degrees flat out. Perfect.
Never ran this low.
Checked both head temps while hot with hand held laser gun. Both within a few degrees.
So the 30 lbs water pressure is still a mystery but we are good to go.

Thanks for the advice guys.

Regards
Doug

Is the 135-140 temp referring to the head or water temp..?

[hastings]

Hello Ted,

I'm referring to the head temp. It is right where you said it would be. Beauty. First time in four years. I thought that when sending units went they just stopped working. No that they changed their readings. interesting.

I guess I will take the heads off and check for some restriction.
I will do soon. Let you know my findings.

Regards
Doug


Is the 135-140 temp referring to the head or water temp..?

[Jay Smith]

Divider plate cross overs also...Place where rock , pebbles, aquatic debree, and wood chips will lodge and cause high pressure and low cooling media flow..
Jay

[hastings]

Will do Jay.
One other question.
My 280 sits on a 260 exhaust plate and tuner.
The water tube from the pump is only 1/2".
Could this be another problem? Should I change?

Regards
Doug