Running Warm After Rebuild

[mike7a10]

I recently completely rebuilt my A4 and it is running great with the exception that it is running a bit warm. I cruise at around 1850 rpm that gets me to about 5.5 knots and the temp is hanging around 170 or so. If pushed to 2300 rpm and around 6 knots the temp gets up to 180 but does not go any higher. I have a restriction valve in the bypass hose that is cranked just about (or is) all the way closed...

I replaced the water jacket in the rebuild and I see that there is a fitting that is offered that screws onto the end of the intake pipe that needs to be drilled with a hole that forces the water towards the back of the engine (#4 & 3 cylinders). I do not have this fitting and the water is shooting straight into to the cooling chamber presumably between the #3 & #2 cylinders at full flow without restriction.

Could this be causing my temp to be a little on the high side?

[rigspelt]

I recently completely rebuilt my A4 and it is running great with the exception that it is running a bit warm. I cruise at around 1850 rpm that gets me to about 5.5 knots and the temp is hanging around 170 or so. If pushed to 2300 rpm and around 6 knots the temp gets up to 180 but does not go any higher. I have a restriction valve in the bypass hose that is cranked just about (or is) all the way closed...

I can't write with authority on this, but I thought that diverter mod merely spread the coolant around more efficiently between the cylinders, but would not necessarily cool the engine more with that modfication. Antifreeze or seawater cooled engine? Are you running in a hot ocean or up here in Canada? Was the exhaust system rebuilt too?

[mike7a10]

The engine was completely rebuilt including having the block and head cleaned, hot tanked and decked. I am confident that the cooling system is fine. (It is raw water/sea water cooled.) As far as the exhaust system I replaced the water lift muffler and all of the exhaust hoses are unrestricted and flowing well.

The sea temp here in SW Florida right now is around 88 to 90 degrees depending on the day. I suppose that this is a likely explanation and will see what happens this fall after the sea temps cool down to the 60's.

Thanks for the quick reply!


Mike
S/V Plan Sea
Punta Gorda, FL

[keelcooler]

I have a new pump and clean jackets. I have drilled the cap for rear flow and she runs at 180 also. She seems to like 180,and cleaner plugs.

[roadnsky]

I do not have this fitting and the water is shooting straight into to the cooling chamber presumably between the #3 & #2 cylinders at full flow without restriction.
Could this be causing my temp to be a little on the high side?

Are you saying that you have no diverter cap?
Your temps are really NOT out of line. I wouldn't worry about them.
But, for a later project, you might want to pull the side plate and put the diverter cap in.
It WILL give you a more "even" distribution of cooling water around those jackets.

[mike7a10]

Yes...the diverter cap is what I do not have in place on the water jacket. Thanks Keelcooler for the info regarding your temp of 180 degrees. It makes me feel better about running at that temp.

Roadnsky...I will definitely add the diverter cap next time I remove the water jacket.

Thanks guys! I appreciate the info!

Mike
S/V Plan Sea