switchbackman

I have a question does any body know how hot it gets inside a engine compartment say with twin stock 454s and stock manifolds. Thanks

buck35

I've wondered the same thing and decided the easiest way to see is with a remote outdoor wireless thermometer in the bilge and carry the base unit up front.

SB

iTrader: (1)

I checked mine. Well of course I did. Any other hotrodders left ? LOL.

I was checking for proper airflow mostly.

Anyway, small single engine boat. Plenty of airflow and circulation. Temp meaured at air entering the carb - cause that's what matter to me - 85F on a 75F day running approx 6 miles at WOT. 120F-130F engine water temp.

Pssst: My K&N 9x3 arrestor cost me almost 3mph on a mild small block.

Another test and tune day, tested My insert mufflers and cost me almost another 3mph.

This is why we test - right ?

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One boat is not another. Some boats have horrible air flow and circulation, which are not the same as each other.

If you have no data about your particular boat and engines, you should check...if you care of course, which sounds like you do.

There is a reason those big bad Apaches had the massive engine compartment venting they did.

apollard

I measured using cheap wired indoor / outdoor thermometers as above - taped sensor in airflow of flame arrestor. Moored after a run on a 95* day, 145F max. After 2 minutes running, 105F. 3 min running, 98F. Stayed right there. I concluded little to be gained, plenty of air flow on my boat.

I paid around $7 w/ shipping for my 'tuning instrument', so very cheap to check your boat.

BUP

iTrader: (9)

Go to Lowes or HD and buy the outside weather remote temp monitor station basically what everyone else said here.

Next test your temps a couple of different ways = if you have proper venting and hose routes / bilge blower(s) then test it both ways - 1 with the bilge blower(s) off and 2nd with bilge blower(s) on all the time. It might surprise you how much the temps can be lowered running the bilge blower(s) all the time.

Merc does not want to see any temp higher than 174 degrees so you need to test the temps after a hard runs and engine shut down - then heat soak afterwards. This will cause vapor lock problems and running problems if your engine gets close to that 174 degree mark or higher.

Back years ago I could not tell you how many boats heat soaked past 174 from not enough venting especially when the rec boats got rid of all the side vents for the more euro look. This trend started around 1998 and MPi engine suffered vapor lock in the deep south and then the OEMs came up with adding boast fuel pump kits along with testing the engine compartment temps to help against vapor lock. FYI

airjunky

iTrader: (2)

Oh yea the texas heat soak efi motors . And holley 4bbl mastercraft direct drives. Had a stars and stripes that 2 blowers and the 600cfm the carb was moving at full boogie couldnt overcome heat soak and turdball ethanol gas boil. Wrapped the lines added a joint duct going up to the carb base from a second mini 30cfm or so bildge blower didnt even have to drop the float levels .circulation is a good thing those old school squirrel cage bildge blowers are a good thing too. If your having issues .