running hot: mercruiser 5.7 w/alpha 1

[zed912]

i have an 88 VIP with a mercruiser 5.7 w/alpha 1. i was on the lake yesterday and the temp got up to 235deg. i shut down for a while and took it back out of the water.<br />i've noticed it gets up to temp pretty quick. also it can be hard to start after it done that,,,, like it flooded.<br />i don't know what the normal operating temp should be. i just bought this boat this year and i'm new the boating scene. today i took the hoses loose from the water pump on the engine and i did not see any water in the block. i would like to try to remedy this problem myself without having to go to a service shop. my wife is getting tired of me investing in something we don't use much..<br />help please<br /><br />thanx,,,,,,ZED

 

[Fouled Plug]

Re: running hot: mercruiser 5.7 w/alpha 1

Do you have a heat exchanger? Is it full of coolant/water mix? If it is, and the thermostat and impeller are in good working order, your circulating pump on the engine may not be operating correctly. How is the drive belt?

 

[zed912]

Re: running hot: mercruiser 5.7 w/alpha 1

belts seem good and tight, when running on the fake lake,,i have water spraying out of the prop,,also from under the out drive,,,,i'm not sure what normal should be.<br />have any clues that i should look for?

 

[hondon]

Re: running hot: mercruiser 5.7 w/alpha 1

Start with at least inspecting and while your in there replacing your w.p. impeller .Take a hard look at the pickup hose between the drive and the transom.Any water leaking into the boat ?If so look at the hose from the transom to t stat housing.All this sounds like a water delivery problem and those circ pumps rarely fail to the point of overheat.

 

[zed912]

Re: running hot: mercruiser 5.7 w/alpha 1

i took the t-stat out,, iran the engine for about an hour and the temp never got over 180deg. no water leaking inside the boat<br />i flushed all the hoses, even the 2 to the heat exchangers, seemed clear. where is the impeller located to even check?<br />i'm not able to check the t-stat due to me destroying it trying to get it out of the housing, it was frozen to the housing.<br />would i beable to run my bout without the t-stat, or is that a bad idea?<br /><br />thanx again,,,,,,,,ZED

 

[ODDD1]

Re: running hot: mercruiser 5.7 w/alpha 1

Zed, that motor shouldn't even register on the guage without a thermostat....the fact it gets that hot without a t'stat means you GOTTA put a water pump in it....if you gotta ask where it is, you better get a professional to change it....wifes may complain about money spent on boats, but if you cant even use it you dont have a leg to stand on.....

 

[zed912]

Re: running hot: mercruiser 5.7 w/alpha 1

i know where the water pump is on the engine,,it's similiar to a car,,,, i'm not sure if the impeller needs replaced on the outdrive, that's the part i'm not sure of where it's located.<br />the water pump or the impeller?? that's the question<br /><br />thanx again,,,,,,,,,,,ZED

 

[clanton]

Re: running hot: mercruiser 5.7 w/alpha 1

Locate water hose from transom bracket at rear of engine to thermostat housing, remove hose start engine ( in water or muffs) rev engine only a few seconds, should be lots of water. Splice in short piece of clear hose run engine look for air bubbles. You heve low water/air replace water pump kit in outdrive. Still overheat check manifolds. If it has been hot enough to be hard to start I would retorque head bolts.

 

[hondon]

Re: running hot: mercruiser 5.7 w/alpha 1

If you do not know when the last time your sterndrive w.p. was last changed then now is the time to do it.This is a regular maint. item ,every two or three years.Plenty of helpon this site if you decide to do it yourself.Pump is in the lower half of your gearcase.