5.7 gsi pwtr possible overheat gremlin

SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
So last year i repowered. 5.7 psi pwtr. I was unable to make any trips as i have been chasing an overheat per my gauge.

Things I've done. I have replaced every hose. New Thermostat. sea water pump. New threw transom fitting. new outdrive hoses. VP sx-M. New seals in the lower.

I installed clear hoses on the sea water pump to look for air bubbles. bubbles are present.

I thought it might just be my temp gage and sender so i installed a new gage sender and wire.. no change

My temps running on the muffs hang at 160-165 then for no reason the gauge climbs to 180-190.. if i put it in neutral and increase the throttle to 1100 rpm for a few secconds, temps will fall to 150.

I shoot the top of the thermostat housing with a temp gun and its about 120.
The intake manifold closest to the temp sender is 112-115

My port riser is about 98. my starboard riser is 125. temps taken on top of riser

My risers have always varied in temp.. both are brand new.

Im stumped, My temp gun readings on the motor indicate im not to hot but the gauge says hey dummy don't cook your new motor..

Any thoughts are greatly appreciated..
 

MATTANZA

old man of the sea, in training.
Aug 23, 2004
5,433
2,911
Cali the state of confusion, the state of shock
Name
RICK
Boat
Boston Whaler 25' Outrage "MATTANZA II", 34' Radovcich "AMY ANNE" {when it needs to be fixed}
get a mechanical gauge. it's more accurate , and not prone to electrical issues. then you can get a real reading. on my friends radovcich, the upper station stb guage started reading high all of a sudden, I immediately checked the mechanical set I installed in the engine compartment. the mechanicals were reading fine. turned out to be a bad sender. on all of the inboard boats I've owned, they all had stewart warner marine mechanical gauges.
 

SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
Thanx for the reply... I’ll look into them
 

SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
Yes raw water cooled.... only cooler I have is a power steering cooler.. it is clean as a whistle...
 

SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
I'm assuming raw water cooled ? Riser meaning elbows... sounds as if you have a gasket mis- installed. Check to see if you have restrictions in the oil coolers.
We’re u referring to the gaskets between the exhaust manifold and riser?
 

SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
has anyone applied any type of sealant on the inside of three hoses to aid in air tight connections?
 

willyok

I've posted enough I should edit this section
Apr 10, 2012
731
222
San diego, CA
Name
Will
Boat
Aloha Lady 33' K&C.
Well if your temp gun is accurate it sounds like you are indeed not overheating. The wire from the temp sender to the gauge may be grounding out somewhere along the way or on the gauge panel.

I’m not too familiar with the GSI series engines. Try to get ahold of a diagram and see if that signal wire passes through a computer or junction block then check resistance values after those looking for significant drops.

I’ve never needed to use any sealant on the hoses.
 
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SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
ok. i taped off the inlet holes on the outdrive. I removed the hose that goes from the power steering cooler to the thru transom fitting. I inserted my garden hose and dribbled H20 until it was almost full. I then jumped down to inspect the connections on the outdrive as per lou's instructions on another forum... I found h20 coming out what looks to be in the area of the plastic fitting #18

https://www.marinepartseurope.com/en...-44-10147.aspx

i was unable to pull the drive as my time was limited.. This part was replaced new as i have been trying to track down the air issue.. Perhaps I may have cracked it when tightening it down... If time permits i will pull the drive tomorrow and inspect...

more to follow.

Thanks for the input guys
 

SD2600

Opinions aren’t constitutional- they are earned
Apr 13, 2017
503
342
39
San diego
Name
Dustin
Boat
26' sea swirl
Alright guys, pulled the drive.... the only h20 coming out of the hose now is from the small drain hole on the plastic fitting.... this leaves me to believe that the air is coming through the pivot housing and drive... lower case b shaped gasket. # 35 ... this was not replaced new when I did the previous hose repairs...

my the boat shop near me had the #35 o-ring. I picked it up cleaned up both the drive and pivot housing. I applied a liberal amount of triple guard to the o-ring on the plastic fitting as well as to the o ring on the pivot housing.. I buttoned it up and a lil triple guard squeezed out the port side.... I fired it up on the muffs and.... drum roll..... no bubbles.... I ran it for probably 15 min and the temp stayed solid at 160... starboard riser was 108 port 90, thermostat housing and manifold 96.. After is warmed up for that 15 min or so i gave it a few 3-5 sec revs to about 1200 rpm... bubbles appeared on the intake side but went away in 5-10 sec.. the temp never climbed... I guess those bubbles are due to lack of supply on the muffs..Next step is a sea trial. not sure when i will be able to go but i will update when it happens.. i greatly appreciate the prompt responses and advice from everyone.. thank you
 

Alexvi

I've posted enough I should edit this section
Aug 6, 2012
215
316
Santa Cruz, CA
Name
Alex
Boat
Rock Steady - Davis Rock Harbor #001
I use the Engine Watchdog on my boats. It's saved me countless times. You put one sensor on the engine block and another one on a riser. You can set custom temp alarms. Worth every penny, especially if you run in the kelp.

http://enginewatchdog.com/
 

skipjack

I've posted enough I should edit this section
Oct 20, 2004
1,022
354
65
santa maria
Name
skip
Boat
2320 Parker "Donna Marie"
I believe you found the problem. Air entering cooling system.
I replaced the same #18 and o-rings on my rig. (Not broken,maintainace)
 
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