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Overheat Alarm at higher RPM's 2002 BF 225

O

Other Line

Contributing Member
When I splashed her for the season I got an overheat alarm within 5 min of start up, so I replaced my T-Stats. All good for about 15 hours or so, but last night as I got to about 4200 I got overheat alarm and it shut down. Started right back up, no alarm, and once I got back to around 4200 same thing happened. Started right back up, no alarm, and idled around the inlet for about an hour with no issues.
Took it out today, and no issues till about 4200 or so then issue returns. Going to pull the T-Stats tomorrow, any other ideas? Never seen one overheat at a certain RPM, then start right back up with no alarms until I get to that RPM level again.
TIA,
The Other Line
 
It is possible that your relief valves #'s 7 and 8 are stuck or plugged with debris/salt. They open up at high rpms to let more water out. If they are stuck, the powerhead does not get enough water flow.

They are located on the port and starboard side of the engine case.

That is assuming that impeller is good and the thermostats are still good and passages are clear.

Just a hunch....

Mike
 
hondadude said:
It is possible that your relief valves #'s 7 and 8 are stuck or plugged with debris/salt. They open up at high rpms to let more water out. If they are stuck, the powerhead does not get enough water flow.

They are located on the port and starboard side of the engine case.

That is assuming that impeller is good and the thermostats are still good and passages are clear.

Just a hunch....

Mike
Click to expand...

Thanks Mike, I can't find my Seloc manual, is that something that I can access easily? Boat is still in water. Just wondering where to find those relief valves
 
I know there's a lot of difference between your engine and mine(BF50) but, that's the same situation I was in.....new impeller
took care of problem. Read "tmike" post
 
hondadude said:
Sorry, forgot to add the link to the parts page. http://www.boats.net/parts/search/Honda/Outboard Engine/2002/BF225A2 LA/MOUNT CASE/parts.html

I think you will probably have to pull the side panels back to get to them. May be a bit tricky to do on the water.

Mike
Click to expand...

Yep, can't do it in the water. I am going to put it on the trailer and take a look. T-Stats are new, impeller and water pump have about 200 hours or so, about 3 years old. Pees like a race horse. I did do some sanding in the T-stat area as I have the dreaded corrosion issue and have JB Weld SteelStik plugging up the pencil tip sized hole in the block under the T-Stat. I was super careful to not let anything down into the block but some residue may have gotten in there. I put about 15 hours or so on it after doing so before this issues cropped up. I will post results. Thanks for all the replies
 
Ok, had a conversation with a neighbor who has some interesting experience with a pair of Honda 115's. He bought the boat used and prior owner had overheat problems. Motors have about 700 hours on them. He changed everything out but still random overheat issues. Here's where it gets interesting: he went and found thermostats that open a few degrees earlier than stock. His reasoning is that as the motors age passages get a little clogged over time. He has and no overheat issues since.
Worth a shot?
 
I'll pipe in on this one, too. As Mike said, check the pressure relief valves first. That would be my first guess.

If I were facing your problem, I would run the boat with the hood off and have a friend drive the boat and I would use a heat gun to confirm that the manifolds are truly over heating - in excess of 180 F.

Your OEM t-stats will start to open around 140 F and should be completely open at 160 F. Full open is only 3 mm. You may want to test them in a pot of water on a burner with an accurate thermostat. It's not unheard of that t-stats get out of specs. I would be reluctant to replace those t-stats with cooler ones. The engine was designed to operate at specific temperatures. Anything significantly cooler could cause excessive wear and end up contaminating your oil with gasoline.

If you are operating in shallow areas it is possible that you may have ingested sand or mud into the water pump and other passages. If the pressure relief valve cleaning doesn't fix it, I would be prepared to replace the water pump - not just the impeller, but the entire pump. It's not that much more expensive than the impeller kit. Over time, the impeller will wear the sides of the pump wall, causing a bad seal with the impeller vanes. At higher speeds problems with a worn water pump seal will more likely show up. When doing that, and with the bottom unit dropped, I would thoroughly back flush the water passages using a garden hose stuck into each t-stat opening and sealed with a rag.

One other observation - at 4200 rpm or around that number, is when the V-TEC (variable timing) operation kicks in. It may be far fetched that the failure of the V-TEC operation would cause an overheat alarm, it is worth noting of all of the above remedies do not fix the problem.

A final piece of advice - throw that Seloc manual in the garbage can and invest in the official Helm Shop manual. It's about $116 on Amazon or eBay. But they are worth every penny based just on the detailed maintenance chapter (3) and the V-TEC diagnostic chapter (5). It will save you many $$$ in the long run.
 
Can't find the Helm manual on Amazon, just one by Honda Marine. Tried the Helm website and couldn't find it there either.
Any ideas on where to find it?





chawk_man said:
I'll pipe in on this one, too. As Mike said, check the pressure relief valves first. That would be my first guess.

If I were facing your problem, I would run the boat with the hood off and have a friend drive the boat and I would use a heat gun to confirm that the manifolds are truly over heating - in excess of 180 F.

Your OEM t-stats will start to open around 140 F and should be completely open at 160 F. Full open is only 3 mm. You may want to test them in a pot of water on a burner with an accurate thermostat. It's not unheard of that t-stats get out of specs. I would be reluctant to replace those t-stats with cooler ones. The engine was designed to operate at specific temperatures. Anything significantly cooler could cause excessive wear and end up contaminating your oil with gasoline.

If you are operating in shallow areas it is possible that you may have ingested sand or mud into the water pump and other passages. If the pressure relief valve cleaning doesn't fix it, I would be prepared to replace the water pump - not just the impeller, but the entire pump. It's not that much more expensive than the impeller kit. Over time, the impeller will wear the sides of the pump wall, causing a bad seal with the impeller vanes. At higher speeds problems with a worn water pump seal will more likely show up. When doing that, and with the bottom unit dropped, I would thoroughly back flush the water passages using a garden hose stuck into each t-stat opening and sealed with a rag.

One other observation - at 4200 rpm or around that number, is when the V-TEC (variable timing) operation kicks in. It may be far fetched that the failure of the V-TEC operation would cause an overheat alarm, it is worth noting of all of the above remedies do not fix the problem.

A final piece of advice - throw that Seloc manual in the garbage can and invest in the official Helm Shop manual. It's about $116 on Amazon or eBay. But they are worth every penny based just on the detailed maintenance chapter (3) and the V-TEC diagnostic chapter (5). It will save you many $$$ in the long run.
Click to expand...
 
Other Line said:
C-Hawk Man- thanks as always. I had that manual originaly, but lent it to my mechanic and never saw him or my manual again. I may have to grab another one as I can't seen to find a Helm manual
Click to expand...

Ok, going to replace water pump and impeller . I see a "water pump service kit" on the boats.net site. Looks like an impeller, gasket, and one other part. Is this what I need? Part number is 183285.

I'd like to replace everything necessary while I have it apart. Any input/advice on what parts are needed would be appreciated.

Thanks,
 
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