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Bf225 overheat. Ideas needed.

S

Stang4u2nv

Member
2002 bf225. So i have always had this issue. With both engines down fully trimmed down i have no overheating alarms. Once im cruising i start bringing up the motors slowly and then one of them will trip the overheat alarm. T-stats are new and inpellers are new as well. Is there a performance water screen for the 225? I know evinrude and mercs have highflow water intakes aftermarket. Does honda have this as well? Thanks guys
 
Don't know about a performance water screen for the 225, BUT, the intake screens can easily get clogged if you have been running through grass or seaweed. They just bolt on, so unbolt them and inspect carefully.

Another issue is engine height. The anti-cavitation plates should be even with the bottom of the hull at the transom. For every foot of offset from the transom (say, for a motor extension) the anti-cavitation plate should be raised one inch. When running on plane, the anti-cavitation plate should be just skimming on top of the water.

Finally, once the alarm goes off, have someone drive the boat while you closely inspect the the anti-cavitation plates and see if they are both skimming the surface. Your trim meter may be indicating that both are trimmed equally, but one may be trimmed up more than the other due to engine torque, unequal weight distribution, or hull obstructions. I assume one of the engines is set up as counter-rotating.
 
chawk_man said:
Don't know about a performance water screen for the 225, BUT, the intake screens can easily get clogged if you have been running through grass or seaweed. They just bolt on, so unbolt them and inspect carefully.

Another issue is engine height. The anti-cavitation plates should be even with the bottom of the hull at the transom. For every foot of offset from the transom (say, for a motor extension) the anti-cavitation plate should be raised one inch. When running on plane, the anti-cavitation plate should be just skimming on top of the water.

Finally, once the alarm goes off, have someone drive the boat while you closely inspect the the anti-cavitation plates and see if they are both skimming the surface. Your trim meter may be indicating that both are trimmed equally, but one may be trimmed up more than the other due to engine torque, unequal weight distribution, or hull obstructions. I assume one of the engines is set up as counter-rotating.
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i had engine heigth problems when i first bought the boat 5 years ago. Engines were too low and had issues getting on plane. Also max rpm wasonly 5000rpm. So i raised them up 2 holes, now max rpm is 56-5700 and picked up 4mph top end speed. Anticavitation plates are skimming the water right now and visible so i think i achieved my goal. It only happens when i start trimming up and she really starts moving that this happens. This boat is bow light so any excessive trimming will cause it to porpise thats why i only do it lightly. Even then she does a solid 53mph. Im not sure what else to do. I have inspected the screens and they are clean.
 
As chawk_man wanted to know, is one outboard cc rotation? Which one alarms?

What is the "spread" between the two outboard's center lines? I'm no expert at this stuff, just thinking out loud about possible "wake interference" from one outboard to it's mate.
 
Sorry guys, boat is a 2002 island runner31’. Yes engines are rotation and counter rotation this only happens at wot and once trimming up. I can go wot and trimmed down and it wont overheat.
 
I guess most of the time it happens on the starboard engine but then again i rarely go wot. Only once in a blue moon or when testing for something. Like this weekend we were testing my brothers 26 freeland and we were near 50mph when i blipped the trim and boom starboard engine limp mode and alarm. Not a big deal but i just know its happening you know. Im about to remove the thermostats and see if it happens again. I know its not a pump issue i can cruise all day for hours and trimmed up and nothing happens. What do you think, should i temporarily remove the stats and see if it occurs? Its a boat and a toy not really concerned with fuel economy.
 
OK, I suspect that those two motors are mounted close together, so as Jimmy implied, you may have a cavitation problem with one of the props interfering with the other. I don't know if there is must of a fix for that except to spread the engines further apart, and that would likely be a PITA.
 
OK to remove T-stats for a very short test period. BUT, if you leave them out, motor will run too cool, allowing water to get into the oil and rapid carbon buildup.
 
chawk_man said:
OK to remove T-stats for a very short test period. BUT, if you leave them out, motor will run too cool, allowing water to get into the oil and rapid carbon buildup.
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Thanks brother, the engines are pretty close together and you maybe correct it may be a water starvation issues when trimmed up at the water screen. I don’t have any cavitation at the props but the screens maybe suffering. I guess i’ll have to test it with the stats out and it sucks because i made sure they are new and installed properly. Will take them out and go for a run. Lets see.
 
chawk_man said:
OK to remove T-stats for a very short test period. BUT, if you leave them out, motor will run too cool, allowing water to get into the oil and rapid carbon buildup.
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For this old guy, that would mean the "choke" was on all the time, so runs really rich because the computer thinks the motor needs to "warm up"?
 
Did this issue persist when your engines were lower? Or is it just happening now that you raised the engines 2 knotches? What about leaving the engines down and running full throttle, does it happen then? Or only when trimming? Can you only use trim tabs and not tilt engine?

Nice boat BTW, always liked the Island Runners! Post a pic!
 
racerone said:
Sounds like motors are mounted too high.
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Not at all racerone, i raised the motors a few months after acquiring the boat. The boat at the time had a gery difficult time getting on plane very light on fuel and only 2 passengers so they definitely needed raising. I also confirmed via max rpms and top speed they were both low. Once upped it was a different boat. If i leave the engines all the way down of course my top speed suffers and randomly one of them will trip the alarm but i would have to keep them wot for a long period of time. But trimming up they almost immediately trip the alarm as if they are starving for water at high trim positions. This is why i was mentioning the high performance water screens that other companies make for mercury and evinrude engines. I thought someone might make some for the 225 but my hopes are not very high right now.
 
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