1993 force 70 hp running hot??

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bob-o p

Seaman
Joined
Feb 6, 2003
Messages
59
i've got a 1993 monark aluminum boat w/70 hp force. i just rebuilt it and it is runnning great, but i ran about 15 or 20 miles this weekend and when i first took off it ran fine, just like it has been running. about 7 miles later i stopped fished about 30 min. left and went about 3 more miles, but it was running about 10 mph slower (25 and it usually runs 35ish) and it did that the rest of the day. the next day i ran it and it ran fine. i thought it might have gotton too hot but the water pressure never dropped a bit. any input will be appreciated!!
 
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bob-o p

Seaman
Joined
Feb 6, 2003
Messages
59
Re: 1993 force 70 hp running hot??

also does anyone know what the water pressure should be? i asked this question before but i didn't get any replies. it has 11 psi wide open and 2 psi idleing.
 
roscoe

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,667
Re: 1993 force 70 hp running hot??

I have a '95 70hp. New impeller. Pressure is 2-3 at idle, 13 at WOT.<br /><br />Could it be you had the trim out of adjustment when it ran slower?<br />Did the engine seem to be getting up to max rpm's?
 
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bob-o p

Seaman
Joined
Feb 6, 2003
Messages
59
Re: 1993 force 70 hp running hot??

yes, the engine was at what it always runs at 4800 rpm. and trimmed like i always do.
 
roscoe

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,667
Re: 1993 force 70 hp running hot??

If the engine was running at same rpm, then I would say your prop is starting to spin the hub. It may have just started, and not be damaged too badly yet, thus the intermitent effect. <br /><br />If you are not familiar with prop hubs, they are a rubber bushing inside the prop. It keeps the hub and the outer portion connected. If you hit a big log, the rubber is supposed to slip, allowing the outer portion to be damaged, but cushioning the impact to prevent damage to the motor.<br />Sometimes they just get old and start slipping.<br /><br />I would put on another prop and try it, and then get the old one re-hubbed at a prop shop.
 
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