1982 seaswirl omc 2.5 running too warm

[ez4sure]

hello everyone i have a 1982 sea-swirl omc 2.5 model # 120FTHRCIS its running to hot going by the temperature gauge reads around 200 running on a garden hose so far i have replaced impeller and all seals in upper gear case new 160 thermostat and new temp gauge, inspected water pump, pulled riser inspected water passages all nice and clear. with engine running temp gauge reading 200 using a laser temp gun im getting around 155 at the thermostat housing below where the thermostat sits any help would be appreciated

 

[Scott Danforth]

If the IR thermostat is reading 155 and your $2 dash gaige is reading 200. Something is wrong with your gauge

First, clean the terminals on tge sender and gaige. If that doesnt fix it, measure the sender resistance to see if its the gauge or the sender that is bad

 

[GA_Boater]

Welcome aboard.

Running on muffs is the worst way to diagnose temperature problems. Dunk the boat and see what it's doing.

But with IR showing 155 and the gauge 200, your gauge or sender seems flaky.

 

[ez4sure]

thanks for the reply's i replaced the gauge new nos gauge i got on ebay also forgot to mention that i replaced the sender too i have a manual and its says to use a 140 then a 170 melt stick just beneath the thermostat so that's where i used the IR. so that's what got me baffled. i bought the boat cheap because of the overheating issue and water in the upper gearcase. and the old thermostat that was in it was a 140, also ran a compression check #1 100 #2 105 #3 95 #4 110 theres is no water in the oil its very clean and the plugs look perfect so i do not think its a blown head gasket but #3 at 95 is a bit low.

 

[Scott Danforth]

All those cylinders are low. Below 120 is time to rebuild......So..... Rebuild time.

Check the wiring to the gauge

 

[ez4sure]

when i replaced the gauge the wiring looked to be in excellent shape, when i did the compression check the boat had not ran in a few months also the books says to use wot so i am going to do a test again this motor runs really smooth and no engine smoke at all would like to get the temp thing figured out before i spend alot more on this boat thanks

 

[southkogs]

If you're going to run the boat on land at WOT - make sure your drive is off the boat. I would recommend you rig a way to circulate water through the engine. OR alternatively - take it to the lake and float it while you run it up. The way the Stringer works, it's hard to "push" enough water through the cooling system without the drive being completely submerged and/or some type of rigged water inflow.

What kind of shape is your upper gear case in? (You said it had water in it.) If your engine is running smooth, then I would eliminate some drive issues if you're trying to do a gut check on keeping/working on the boat. The Stringer is a drive to be considered "vintage" - read that as "parts getting harder to find." If your upper gear case is toast, you'll have some work ahead of you either repairing or replacing it.

 

[ez4sure]

Thanks kogs I meant I was going to do another compression check with the throttle wide open will also warm up the engine first last test it was cold . Upper gearcase all parts looked in nice condition so I replaced all seals and new impeller kit . I will try running it in the water next to see if it runs cooler. Also might run a new ground wire from engine to under the dash in my years of working on cars I have seen bad ground cause alot of problems. I will let you all know what happens thanks

 

[ez4sure]

hi everyone so i ran the boat in a lake for a little bit, gauge still reading around 200 so went back home hooked up old gauge next to engine with short wires going to sender ground and battery still reading the same so i pulled thermostat housing and front plate off the manifold every thing looks clear started engine on the hose with that plate off manifold water flow seems ok about a gallon came out in less than a minute any thoughts thanks

 

[Scott Danforth]

define less than a minute. the pump should be able to fill a 5 gallon bucket in about 30 seconds while just above idle

 

[ez4sure]

Was not near that much I started it up for about thirty seconds and got about gallon out of the front of the manifold where I took the plate off but this was running on the garden hose

 

[ez4sure]

Took the new thermostat out tested in a pan on the stove it opened at 160 just like it should I guess I can pull the manifold next. about pull my hair out lol

 

[Scott Danforth]

you are low on flow. when you replaced the impeller, were any of the old blades missing?

if so, did you go looking for them?

stringer water flow is from inlet in lower, thru water pump up thru upper, out thru the trunnion caps, thru the intermediate, up a hose to the thermostat housing.

stringer flow is lower than say an Alpha, Cobra or volvo, however it should be about 12 GPM at 1200 RPM.

you are testing it in the water, correct, and not trying to suck up from a bucket (that doesnt work)

 

[ez4sure]

I have the ear muffs on with garden hose I guess I better take it to the lake and retest I will keep you posted thanks

 

[ez4sure]

Also old impeller was intact on this boat water goes from intermediate housing to the riser

 

[Scott Danforth]

if your on muffs, the hose needs to be 5/8" or larger and the water on full.

 

[southkogs]

There's also a circulation pump on the front of the engine. That should be pushing water through the inlet hose to the stat ... how's the pump?

 

[Scott Danforth]

Also old impeller was intact on this boat water goes from intermediate housing to the riser

Something is not right if the hose from the intermediate housing is plumbed to your riser

 

[ez4sure]

Hey Scott I did a flow test on the manifold hooked up the garden hose with valve took 33 seconds to fill a five gallon bucket half full then hooked it up to the water inlet on the riser another hose coming out of the manifold where cold water goes to the top of the thermostat housing took 38 second to fill same bucket half full but I noticed some water coming out the other side of manifold where the hot water goes from bottom of thermostat back to manifold hope I'm making sense lol. so must be crack in the manifold leaking from one passage to the other unless that's normal any thoughts. Thanks

 

[ez4sure]

Sorry did not notice a 2nd page with you last comments I pulled waterpump of engine looked perfect also could see in the block and all passages looked clear I can take some pictures of the way the hoses are routed and post them. When bought the boat title says it's a 82 so ordered a manual for a 82 then realized that the engine is a 81 so my manual shows the hoses being routed totally different .