Logo
FULL SITE MENU

BF200A2 Thermostats and overboard discharge

C

Chachy71

Member
ISSUE: How long does it take for the overboard discharge to start working?

BACKGROUND
I just bought a used 1990 S2 Pursuit 265 with twin 2002 Honda BF200A2 with under 900 hours. When I looked at buying the boat both engines started. The boat was in dry storage and we had to use earmuffs to run the engines. The stbd engine had a good overboard discharge and the port no discharge. We did run the engine long enough to check for codes (only the O2 sensor and a low throttle voltage I think) and ahead and astern propulsion. The no discharge issue was a crimped hose to the overboard connector.

THERMOSTATS
Since then I started tearing into the engines since it had been sitting for a year to get a handle on how she had been treated. I found a number of issues but I found all 4 thermostats missing and corrosion where the thermostat sits, I had to scrape it to get the new thermostats to fit, not much but some. I did a test run on the stbd engine with the earmuffs and there is no overboard discharge (no pee stream), I don't run it longer than a minute to avoid overheating and I did it a couple of times but no overboard. The water does come out of the prop but not the overboard. I also took the hose off the thermostat housing and there was no flow there either.

I did get overboard discharge when I put the hose into the thermostat hole in the block. The yard owner says he has low water pressure and the block may not be filling with water. I haven't put it in the water yet since I'm waiting on fuel filter parts and a new thermostat housing for the port engine.

My question for the board is does this sound right? Why would it work without thermostats but not with thermostats? Did I just not wait long enough?

Thanks in advance and I look forward to your learned response.

ps, I'll post my other issues separately to avoid a long rambling post.
 
My twin 200s start peeing within 30 seconds of running. You really need to check this by running in a barrel as water pressure in a hose /muffs will affect the true outcome.
 
Running with no thermostats is a bad thing for several reasons. The question is why were they removed. The motors have PRV or popit valves that open to relive water pressure in the cooling system at higher rpm. It is possible that they are damaged or stuck open not allowing water pressure to make it to the top of the motor. I personally have had a good battle with this subject and my solution was to run barnacle buster through the blocks to remove all the built up salt and corrosion that was blocking a passage in the block somewhere and it worked very well for me. My prv's were a little curded up but not hanging open. I hope the t stats were removed and not just broke down and floating around in the cooling system which i think would be highly unlikely. My motors had 360hrs at the time and the previous owner putted around maybe onece a week and tilted them up. It was a great way to built up salt in the cooling system... running in a barrel is key to start your investigation..
 
Thanks for the responses. I'll check the shop manual for the PRV valve locations.

I rcvd some of the parts today and I'll get her back in the water for dock trials Fri/Sat. We'll see what she looks like when she has more water. I'm hoping it was just a lazy mechanic who couldn't wait for parts. We have to order all Honda parts so I'm leaning (hoping) towards ineptitude not malice.
 
Both started up and ran fine. I ran two hoses, one earmuffs and another on the flushing hose. Thermostats opened as designed and I was able to run both engines.
 
Don't run the engines while using the flushing hose. Flushing water goes in one direction, water pump runs water in the opposite direction.

The big Honda's tend to overheat on muffs, unless water pressure is really high and muffs are really tight. Use a barrel for testing.

FYI - the poppet relieve valves are on the mount case to the rear of the engine. To get to them you need to remove the upper cowlings. To remove the valve itself you only need to remove the two outer bolts. The one in the back just holds the two pieces of the cover together. See: View attachment Pressure relief valves.pdf
 
That is good gouge. I didn't know I was counter acting the water flow and thanks for the pressure relief diagram. I'll pull those apart.
 
Back
Top