honda 225 4 stroke overheating

honda 225 4 stroke overheating

Sounds like you have a blockage in the water jacket beyond the t-stat opening. That is very difficult to reverse flush from the bottom up, and I have never tried it. So, I would try to flush out from the t-stat opening. First, pour in a mixture of SaltAway (or similar) and let it sit for a day. Then block the inlet of the T-Stat opening with a rag and use a garden hose , stuff the end into the t-state opening, and seal it the best you can with a rag and duct tape, turn the water on full power, and see if you can open it up. Put a large bucket under the lower unit to see if anything comes out.

thanks chawk i had the thermo out and hose disconeted started motor water came out finetook exhaust man off used garden hose seemed fine do you think mabe theres blockage where the man goes into the lower housing????

Okay, I'm having a difficult time understanding what you have done, so let's start from the top.
Are you running in fresh water or salt water?
Have you dropped the lower end and inspected the water pump impeller? I know you are heating up on the starboard side, but what temperature reading are you getting on the port side? It is possible that the port side is heating up, also, but not enough to trip the alarm. Normal operating temperature is 160 F.

When you took this heat reading were you in the water or out of the water using a test tank or muffs? If the latter, was it a test tank or muffs? If you were using muffs, or a SMALL test tank, that reading is unreliable. You need to take the heat reading either while the boat and motor are in the water or in a large test tank.

It sounds like you are testing the water passages beyond the water hose that comes off the t-stat, is that correct? It would seem unusual to have a blockage where the manifold goes into the lower housing - I don't think there are any narrow passages after the manifold.

If there is a blockage (as opposed to a faulty water pump), then it is more likely around the cylinder walls in the block - that's why you need to back flush from the t-stat opening - down in the section where the t-stat sits in its housing - that is where the water flow is coming out of the block. It is best to do that with the lower unit out and the water pump out.

You said you removed the head gasket? Are you sure you removed the cylinder head gasket - that's one heck of a job. Or are you talking about the manifold gasket?

chawk thanks for your time lets see if we can make a little simple right now the head is off before taking off head took out starboard thermo took the hose off at the top of exhaust man left hose dangling and started motor plenty of flow rehooked up hose ran motor no thermostat used heat gun after 4 or 5 min starboard side at the top by heat sensor 206 port side with the thermostat 148 i am going to be back on this thursday ps we are a merc and yamaha repair shop should have sent this one out i think p s the boat runs in salt water and we where yousing the rec shaped ears man was flushed and it was clear thanks

The retangular-type muffs don't work well on the Honda 225. Don't know exactly why, but they don't. In fact, no muffs will give you an accurate reading. You need to use a big test tank, or test in the water.

Also, the 225 tends to run a bit hotter on one bank than the other - at least mine does, and always has. Don't know why that is, but clearly not that much difference. Max difference I have seen is about 12 degrees F under load.

There is a tube at the bottom of the manifold that goes back into the case mount and I bet that corrosion has collapsed the hose restricting flow at higher speeds.
Joe

Joe - that is a possibility, but that is a pretty big diameter hose and I have never heard of them clogging up. And everything south of that hose is also pretty wide open. What bcclew is describing sounds like a blockage in the block, possibly due to a disintigrating water pump impeller. Hopefully he will give some feedback when he finds the actual problem.

It happen to me where the hose goes back into the case the corrosion was enough to calapse the rubber hose.. Don't know if that is his issue, but you should be able to just disconnect from the bottom of the water jacket and pull that tube out. Mine would not and ripped and Ihad to dig the rest out. Just something to check.
Joe

ok guys cat out of the bag joe hit it right on the hose from the exhaust man where it goes in yo block was collapsed at the block side my mistake never took hose out to look just ran water through it lesson well learned take hose out and look at it thanks for all the help //////bcclew

Well darn. That's why I love this forum - I learn something new about every day. Glad you found the problem, and I'm properly chastized for not having the correct diagnosis. Thanks Joe for contributing to my education about Hondas.

This seems to be a common problem on the 225, deposits (salt or calcium?) building up. I noticed some deposits around the hoses you mentioned, removed the hoses and they were caked where the hose enters the block. Also had deposits around mid-shaft bushing, causing it to distort and wear the driveshaft. I now make it a habit to pull the temp sensors and thermostats to remove as many deposits as possible. My engine has only 310 hrs. and I flush it after every use w/Salt Away.

http://www.marineengine.com/boat-forum/showthread.php?378110-Alarm-but-no-codes-2003-200-hp

Look I took my boat up to a honda tech to have mine fix and cost me $2000 and still did not fix my problem and they broke my mid case . I took the advice from you guys here on the forum also. JJ_LYNN is me.