www.iFourWinns.com

was out running boat new boat to me and was doing great all day, it sounded great all day. came to a no wake zone and continued slowing when i noticed oil pressure gauge barely reading any oil pressure. motor still sounded good with engine temp around 160-170. i continued running motor till i put it on the trailer 10 mins later. temps never rose nor did it make a single unpleasant noise. when i got boat home pulled plugs and they look brown/tanish in color. is it possible oil pressure sender is bad or wrong oil was used.im gonna change sensor and put in 40w since im here in the south and not sure of the hours on this motor. a little confused and help is needed.

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1988 freedom 160 3.0

What oil was being used when you had the issue with low idle pressure? I ask because sometimes if you used a multi vis oil they will thin out when hot and give low pressure readings at hot idle after running for a while. OMC specified straight 30 but you could use a straight 40 if you wanted to esp on an older engine. I use straight 40 Chevron Delo 400 in my 88 4.3, the lowest hot idle pressure I have seen is about 20 psi. Usually runs at 55 psi on plane. Normal oil pressure for the 3.0 engine from the manual is 40 psi at 2000 rpm. You can try checking the sender as well. I never had a 3.0 but at idle most Chevy engines have at least 15 psi at like 800 rpm, thats what's listed in the OMC shop manual. Normal idle speed with a Cobra drive should be not more than 600 in gear in the water....

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

When I bought the boat the previous owner claimed the oil was changed and yes it does look clean but unsure of type and weight was user's

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1988 freedom 160 3.0

While its not unusual for some marine engines to register low oil psi while coming off of plane (some engines are spec'd to run with low oil psi at idle, as low as 5psi!), I suspect either the grade the last owner used it too thin or its diluted.

When I bought my boat, the last owner said he just had the oil changed too and on the dipstick it looked honey-colored, so I figured it was clean. However, when I was coming off of plane, I'd get a lifter ticking like a mother trucker. The oil pressure would drop to just about 0 on the gauge, although on plane it'd register 40-60psi.

Changed the oil - although it looked nice on the dipstick, it came out black and really thin. I have been using Chevron Delo 15/40 ever since and havent had any issues with ticking or low oil psi when coming off of plane. I bet the last owner of my boat probably used 5/30 or something that wouldnt hold up to extended high RPM's like how we use our boats. Just my $.02

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1997 Four Winns Vista 278
T - 4.3l EFI
Kohler 4esz Genset
379 hours as of 8/8/21

all i can say is thank you for your inputs. its sad but i can build custom motorcycles and hotrods but when it comes to boats, i feel like a idiot......lol.

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1988 freedom 160 3.0

don't fear that engine, it's about as simple and easy to fix, as any marine engine ever was....and if you want to be sure about the oil pressure you can always hook up a manual gauge to verify if your readings are right. For now change the oil n filter, put in either straight 30 or 40, or even the Merc 25/40 stuff, just don't use a conventional car multi vis like a 10w30 they will thin out after running on plane.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Yeah I was running about 35mph all the way across the lake at about 4500rpm. Even with the trim in its sweet spot, that's all she'll do. Does that sound about right or should I suspect something not right. I have no idea what this boat should do as far as performance goes. Now friends say I should GPS it cz it feels though as we are going way faster and my Speedo may be wrong. Any thoughts?

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1988 freedom 160 3.0

Definitely check the speed with GPS. Some boat speedo's are surprisingly accurate (I got lucky), but many are way off. At 4,500rpm and assuming you have the right prop I'd think you could do a bit better on speed, but I'm not a 3.0 expert.

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Mike
2005 Four Winns 230/240
VP 5.7GXi/DP
1998 F-150 XLT
Boat Pic

If it was me, I would change the oil and filter ASAP. It can't hurt & it's cheap to do! As other people have said, there could be something in the oil. Filter could be getting dirty, and the by pass in the filter has not kicked in yet....

I always try to do the simplest things first in trouble shooting.

My 2000 Four Winns H180 with a 3.0... Rotella T 15w40

Idle oil pressure is always 18-20psi

3500rpm oil pressure depends on ambient air temp. Middle of the day 95* air, 90* humid, no clouds.... 40psi
Dusk... low 80s air temp, cool breeze off the water... 60psi.

Being that your boat is a 1988, I'd just replace the oil pressure sender. They're a few bucks at your local auto parts store. Chevy oil senders are typically 100% correct 50% of the time.

I also never run my boat over 4000rpms. I like my engine.

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1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

I just want to understand!! Why would the ambient air temp change the PSI reading?? With the engine warmed up, that would drive the dampness out. Also, the engine would be running at about 175 deg. I am in Boston, and on a warm 90 deg day, the psi has never changed enough for me to notice. The water temp here, is alway 55 to 70 deg, for the past 4 weeks it has been about, 66 deg. Maybe some other parts of the country it could be different, which would cause the PSI to drop??

I don't run a thermostat. Water temps are in the mid 90s, air in 100s. Engine varies from 140 to 170

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1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

Oil pressure typically varies with engine (coolant) temp. When I first start my engine, the cold slow idle shows about 40 psi, after a few runs on plane, the hot slow idle pressure will be 15-20. A few times I have had issues with a sticking open thermostat. While fishing in the Sound, I will leave the engine idling just in case I have to get going in a hurry (big boat wakes). When the thermo gets sticky, and the engine temp drops from like 165 down to 120 or so, you can actually see the idle oil pressure rise up to 40 again...

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

With our lake being so hot right now it's actually too dangerous to swim in. One girl already died the next town over from the dreaded amoeba last week. All I use the boat for now is just a taxi to the resort style apartment complex across the lake where we play volleyball, grill, pick up girls and swim in the pool.

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1981 Columbia 8.7
2015 Yamaha FZR - 87mph - sold
2006 Yamaha GP1300R - sold
2003 Chaparral 215 SSI - sold
2009 Stingray 195CS - sold
2000 Four Winns H180 - sold
1976 O'day Daysailer II - sold
Rick's Four Winns H180 Mods/Upgrade Thread

Thanks, that I understand and fully agree on. The air temp, I don't, other than the oil should be a little thinner at 90 vs a 70 deg day.