1989 7.4 formula 223 running warm 180

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oldfartson

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hello I am having some troubles with my freshwater raw water cooled formula, when i put her away last year she ran all day long at 150 degrees, now this year shes getting up to 180 when giving it the gas, then cools down to 160-170 when going slow. I replaced the impeller, old one was still 100% intact but getting worn. I flushed system, ps cooler and hoses no weeds or clogs. changed thermostat (143). replaced check balls. good flow coming out of the exhaust, except on the port side the water is coming out cool whereas the other side it comes out hot. riser blockage? risers dont seem to be getting that hot to touch, where do i go from here? 1989 7.4 merc, bravo 1, freshwater, sits on trailer. thanks guys
 
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joeypizzano

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Re: 1989 7.4 formula 223 running warm 180

oldfartson said:
hello I am having some troubles with my freshwater raw water cooled formula, when i put her away last year she ran all day long at 150 degrees, now this year shes getting up to 180 when giving it the gas, then cools down to 160-170 when going slow. I replaced the impeller, old one was still 100% intact but getting worn. I flushed system, ps cooler and hoses no weeds or clogs. changed thermostat (143). replaced check balls. good flow coming out of the exhaust, except on the port side the water is coming out cool whereas the other side it comes out hot. riser blockage? risers dont seem to be getting that hot to touch, where do i go from here? 1989 7.4 merc, bravo 1, freshwater, sits on trailer. thanks guys
Click to expand...

You are on the right track pull the risers.
 
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oldfartson

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Re: 1989 7.4 formula 223 running warm 180

Pulled risers off, there was some flakes of steel and some small chunks of iron. I blew them out with air as well as the manifolds. I dont know yet if that was the problem, I will put it together today and report my results.
 
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joeypizzano

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Re: 1989 7.4 formula 223 running warm 180

oldfartson said:
Pulled risers off, there was some flakes of steel and some small chunks of iron. I blew them out with air as well as the manifolds. I dont know yet if that was the problem, I will put it together today and report my results.
Click to expand...

Should always pull your risers every 3 years. Replace them about every 5. How did your manifolds look? Those tend to last a lil longer every 7 yrs. then again are you running in freshwater or salt?
 
tpenfield

tpenfield

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Re: 1989 7.4 formula 223 running warm 180

oldfartson said:
hello I am having some troubles with my freshwater raw water cooled formula, when i put her away last year she ran all day long at 150 degrees, now this year shes getting up to 180 when giving it the gas, then cools down to 160-170 when going slow. I replaced the impeller, old one was still 100% intact but getting worn. I flushed system, ps cooler and hoses no weeds or clogs. changed thermostat (143). replaced check balls. good flow coming out of the exhaust, except on the port side the water is coming out cool whereas the other side it comes out hot. riser blockage? risers dont seem to be getting that hot to touch, where do i go from here? 1989 7.4 merc, bravo 1, freshwater, sits on trailer. thanks guys
Click to expand...


I had that same problem last year on my 7.4L Mercruiser / Formula 242 . . . I checked everything . . . replaced a few things. I finally found what I believe to be the cause when I took the outdrive off. Barnacle fragment was lodged in the cooling hose leading from the outdrive to the transom assembly.

If you don't get any results with cleaning out the exhaust manifold and risers, take a look in the outdrive, etc. for something that may have been sucked up and lodged in the inlet hose (even though you are fresh water). BTW - make sure to use fresh OEM style gaskets for the re-install of the risers.
 
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oldfartson

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Re: 1989 7.4 formula 223 running warm 180

pulled risers, some rust flakes nothing too bad. blew them out, reinstalled oem gaskets, brought her to the lake and still the same. going to take of the circulating pump today and try new gauge....still dont understand why i have cool water coming from port side exhaust? and hot from the other? same flow
 
tpenfield

tpenfield

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Re: 1989 7.4 formula 223 running warm 180

oldfartson said:
pulled risers, some rust flakes nothing too bad. blew them out, reinstalled oem gaskets, brought her to the lake and still the same. going to take of the circulating pump today and try new gauge....still dont understand why i have cool water coming from port side exhaust? and hot from the other? same flow
Click to expand...

Up at the thermostat housing there are the feeds to the manifolds and risers/elbows. There is a mechanism inside the feeds to the elbows that restricts the flow a bit, forcing water through the engine, etc. If this is clogged or non-existent, then you can get an imbalance of flow (port vs. starboard), and perhaps not enough water going through the engine.
 
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oldfartson

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Re: 1989 7.4 formula 223 running warm 180

A buddy let me use his ir gun yesterday, hottest point i could find was 145 in the front of the manifolds, the rest of everything showed 115-125, at the sensor by the thermostat it never got over 115, while the gauge was at 180? I think the gauge is bad? going to change the gauge today.
 
tpenfield

tpenfield

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Re: 1989 7.4 formula 223 running warm 180

Formula used VDO brand gauges back then, it could be a bad gauge, sender, or even an incompatibility between the two, if either has been replaced along the way.

You can still buy the VDO senders - VDO is now a Seimens company. The gauges were either 'Blue Line' or 'Vanguard' series, but I do not believe those are part of their current product lines anymore.
 
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oldfartson

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Re: 1989 7.4 formula 223 running warm 180

Well, put a different gauge in today.... and steady 150-155. now i will be able to sleep tonight! thanks guys for all the help!
 
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