johnson gt 175 - no water flow to heads

blomqvistjs

Seaman Apprentice
Joined
Jun 5, 2016
Messages
41
long story short
new impeller
new headgasket and deflectors in cylinderblocks
new tstats


everything oem from bombardier.


engine still runs hot and without tstat covers i can tell its dry

how does the water flow from impeller
 

jakedaawg

Rear Admiral
Joined
Jun 26, 2012
Messages
4,275
Have you tried back flushing? Remover lower. Remove stats and whatnot. Use a hose to force water backwards and out water tube. There could be old pieces of impeller.
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
Water flows from the pump and into the exhaust chest cooling jacket, then it flows into the block, up and around the cylinders, then passes through the head gaskets and goes around the heads then to the thermostats and out.
 

blomqvistjs

Seaman Apprentice
Joined
Jun 5, 2016
Messages
41
somehow i got the plastic piece wrong and impeller was spinning on the shaft.. time for another new impeller 63?
how can the plastic pice be in the wrong place can i really push down the impeller so hard that it wont stay in place?
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,428
That is because you put the drive piece on the shaft first.------Then install the impeller on the shaft and confirm the key is driving the impeller.----Then lower the housing down while rotaying the driveshaft.---Install and tighten the screws.---------Never mind what the manuals say !!
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Have you had a look down the water galley between the two halves of the block? (under the combination regulator/rectifier.) That needs to fill with water to correctly cool the block when the engine is running. What you find inside that gallery may also be around the cylinders....
 

blomqvistjs

Seaman Apprentice
Joined
Jun 5, 2016
Messages
41
replaced water deflectors and my heads was very clean. no marking so i think nobody since it was built have changed deflectors or have done headwork since 1990. after blowing air trough water pipe from impellerhousing it has no restriction.
 

sutor623

Rear Admiral
Joined
May 23, 2011
Messages
4,089
Probably didn't damage the impeller here. (You said you were going to replace it again.) Maybe you can take the old impeller key and see if it works.
 

interalian

Commander
Joined
Jul 23, 2009
Messages
2,105
My last kit came with an o-ring that goes between the bottom of the impeller and the wear plate. Cute instructions were to fit the key to the flat spot in the drive shaft and hold it in place with the o-ring, centered on the key. Apply some Triple Guard grease to the impeller fins and slide it down. Made it pretty easy to keep the key aligned. Then the usual hold the cup over the impeller and rotate the drive shaft clockwise until the impeller fins form to the cup.
 
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