1988 mercruiser 5.0lx/alpha1 gen 1 expert needed

newtoboat101

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i have 1988 mercruiser 5.0 lx /alpha1 gen1 ,water is only picked up from outdrive (brand new sei 06/17)and pushed to motor , osco4354 risers/restricted riser gasket thermostat housing is only 4 outlets no check balls ,also thermostat housing looks to be the correct themostat housing (has only 1 plug opening )where bravo style has 2 plug openings. the water inlets on the risers from style of thermostat housing with check balls is plugged off (see pics) heres my question and problem first WHY a restricted (pencil hole style) gasket ,seems i have problem with getting enough water thru motor out the exhaust its either good flow on port side and little on starboard side or vice versa ,i can make the flow change sides by pinching off water , good flow side for a minute then flows other side ,then un pinch hose ,good flow doe n't comeback ,can i switch to open flow gasket and correct this problem or is it a vacuum issue ,if i turn off motor and start again sometimes it changes good flow side,took riser off and cleaned out ,put new gaskets on but same issue any ideas as always thanx p.s. do this style engine /outdrive come with water pumps?
 

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wellcraft-classic210

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Finding your post a little hard to follow -- But it may be its just me.

---Can you post some pics of the gasket you are referring to ?

-- Also if you pull the 2 rear smaller diameter hoses are their any spring loaded white plastic check balls ?

Perhaps an exploded view from the manual or a parts site would help here ??????
 

Bondo

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thermostat housing is only 4 outlets no check balls

Ayuh,.... I chased a over heat at idle problem for years, til I figured out I had a Alpha, Gen.II motor in front of my Alpha 1 drive,....
I'd done a major refit with mixed parts, 'n pieces,.... I also didn't know nearly as much as I thought I did 'bout I/Os back then,...

The Alpha 1 flows considerably less water than the bigger pump in the Gen.II drives,....

I put the check-balls in my t-stat housin', 'n haven't had a problem since,....

My guess is, in yer up-datin', ya got incompatible bits, 'n pieces,....
 

newtoboat101

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its not over heating ,one riser gets hotter than the other but not over heating its more about flow , I did put pictures up ,no check balls this is called style III thermostat housing application look on sierra marine catalog 2017 page 725 ,its the last 1988 mercruiser 5.0 lx/alpha1 gen 1 , I believe I have correct engine/outdrive application,you definitely know more than me,bondo ,how about adding seawater pump? can it be done on my engine/outdrive
 

newtoboat101

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sorry ,bondo what would be incompatible parts thermostat housing or riser not much else going on there
 

achris

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its not over heating ,one riser gets hotter than the other but not over heating its more about flow ...

If that's the case, you don't have a problem. It's normal for one side to be hotter than the other, and pinching off the hose going to the cooler side will cause the water to follow a new 'path of least resistance', and go via the other elbow (not riser. Risers are the extension sections that allow the elbow to be placed higher up, in the case of boats with an engine sitting very low down).... riser.PNG
 
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achris

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sorry ,bondo what would be incompatible parts thermostat housing or riser not much else going on there

The incompatibilty Bondo is referring to is using Gen II engine cooling system parts (specifically the thermostat housing) on an engine being supplies water form a Gen I drive. Gen I drives have a much lower volume pump. That's why they needed the check balls in the outlet side, to not allow water out of the engine until the thermostat opened and allowed the pressure of the incoming water behind the hot water to push open the check balls. If you have a Gen I drive, you need a thermostat housing designed for a Gen I drive..

Just looked at your pictures. :facepalm:. You have a Gen II thermostat housing (and plumbing) and a Gen I drive. Never going to work properly. The reason you are working (at low speeds) now is because of the restriction gaskets. They are holding the water in the block. Once the engine demand gets up, those holes are going to restrict flow and the engine will not be able to cool properly. Those blocked off elbow inlets... :nono: You need to get the right thermostat housing with check balls, a new set of hoses (from the thermostat housing to each elbow, and the bottom of each manifold), and set the system up correctly for the engine to cool properly.

This is what your system should look like.... cooling.PNG
t-housing.PNG
 
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newtoboat101

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this is style cooling i have should be correct set up ,right idk, took from crowley marine standard cooling system for alpha , other setups aren't for alpha ? so why the check ball style i have alpha 1 gen 1 outdrive
 

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newtoboat101

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i think this is style i should change to what do you think,doesn't say for alpha or bravo but the engine is correct
 

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Bondo

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so why the check ball style i have alpha 1 gen 1 outdrive

Ayuh,.... The Alpha 1 drive water pump just doesn't move the volume of water the Gen.II pumps move,...

Ya Need the check-balls, or it's gonna overheat,.....
 

achris

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this is style cooling i have should be correct set up ,right idk, took from crowley marine standard cooling system for alpha , other setups aren't for alpha ? so why the check ball style i have alpha 1 gen 1 outdrive

Nope. That thermostat housing is a Gen II. I don't know where you are being told that's a Gen I, it's not.
 

achris

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i think this is style i should change to what do you think,doesn't say for alpha or bravo but the engine is correct

That's the early style thermostat housing. You're better off with the later style, like the diagram I posted.
 

newtoboat101

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you are totally right ,this mfers for big block found info on perfprotech.com under changes to mercruiser parts thermostat housing ,and your right better going with your set up thanx for your knowledge greatly appreciated
 

newtoboat101

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update: i found an a3 design thermostat housing with alpha stamp , i put 160 degree thermostat in /cork gasket and plastic sleeve , i also switched out the restricted riser gasket. with the open flow style riser gasket . start up ,let run ,water is now flowing evenly and risers are cooler ,both sides,but the temp just keeps rising ,so i replace 1 temp sender starboard side ,but still temp keeps rising and the thermostat housing is very hot ,so now i have taken thermostat and cork gasket out , start up,and run temp goes up to 160 degrees and stays there riser are cool, motors cool, thermostat housing is cool and flow is good and even ,so why is it running fine without thermostat did i have thermostat upside down ? i don't think its possible, thermostat will hit thermostat housing ,i am at work now ,but will be boiling thermostats in water later to see if my brand new thermostat didn't work,, but why ,anybody else have this happen
 

Bt Doctur

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running without a stat at 160 deg means your still running hot from some sort of restriction or low water flow
 

newtoboat101

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bt doctur ,what would you do next ,how do find some kind of restriction or should i try another thermostat,first ?thanx
 

newtoboat101

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ok so i went a digital laser infrared temp gun ,start motor let run temp gauge slowly move to 200 degrees ,so put gun on motor ,thermostat housing ,heads ,valve covers ,and each riser and exhaust all the temps were in the 120 to 140 range,starboard riser was the hottest object going to 160, when i shut motor off starboard riser got up to 186 .5 degrees before cooling , that was hottest object ,so what i can tell is its not my thermostat housing or thermostat ,but something wrong with temp gauge ,should i just get new gauge or is wiring not correct or thermostat not grounded to show correct temp ? my thermo housing has 2 sensors i did replace starboard side sensor [h=1][/h]
 
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