I have twin 502's with b1's and I am concerned about the low water pressure on my starbord engine. At wot port engine is at 25-30 and my starbord engine is max 10 psi.

I fried 2 imco maniforlds recently on the starbord so I am very cautious about flow.

Where should I start to look to help improve water flow???

other stats that may help. both engines op run at 60 psi
engine temps on both at 225- 240 degrees.

port engine just rebuilt, starbord no problems but not sure of history was told it was a create engine, no funny noises, no leaks, compression 140-160 on all holes.

Oh help me wise brothers, I like going WOT but am concerned about water pressure so I stay at 3k and blast up for short burst.

Thanks in advance

We need more info-

Has this always been the case or did it just start?
What type of water P/U?
What type of pump?
Where are you reading water pressure?
Are you using crossovers?
What type of exhaust?

I had the same problem on my 32 Fever with twin 502.One engine ran water pressure up to 30 psi at wot.The other engine only ran at 18-20 psi at wot.I completely went thru the low water pressure engine,including new impeller and housing and pressure stayed the same.Then I decided to change the thermostats on both engines and I noticed on the high pressure engine the hose bibs on the thermostat housing were chipped and flaking do to corrosion.When I looked inside the housing it was almost totally clogged with the chipped pieces of metal.When cleaned out both motors ran at the recommended 18-20 psi.Hope this helps.Also check oil cooler for pieces of impellor on low water pressure engine.

Nordic95

ok start at square one check impeller and wearplates assuming there is no restiction at the drive if all looks good pull the housing off on the inside of the transom where the intake hose attaches, check to see the the hose is not restricted ( what happens is the hosing will corroid and squize the hose from there check stat and manifolds although ussually if restricted after the pump you will get very high press and low flow.


if I lost you give me a call and I will explain better

guys, all good stuff and I will check all suggested areas-
Q1-oil cooler do I remove competely to check for blockage -i.e. impeller pieces
Q2-can I get to the inside transom hose without pulling engine.

more info as requeted from zt260.
purchased boat jan of last year- port engine had seized due to salt water in cylinders posibly from cast iron ex. manifold. rebuilt port engine only, added imco powerflows on both engines- after rebuilt on 1st 5 hrs of long burst at wot starbord new imco overheated, melted gasket and damaged manifold. slight water reversion noticed, shut down engine. removed plugs, flushed with wd 40 replace 1 set of imcos, inspected both and good to go, idles great.then replace impeller on sea pump. Went for test today and noticed low pressure on starbord engine and oil temp was raising close to 260 and pressure was < 12psi at WOT. Port engine (that was just rebuilt) is 25 30 psi. with 220-240. At idle, it appears to be getting good flow as it spits real well out the back, but at wot is the concern.
-no crossovers, i think oem water pump/recirc cooling system
-std pickups on bravos but does have nose cones that were added by prior owner
-I am not sure what type of pump -what should I look for to determine-style or brand?
-i think the pres sender is in the thermo housing(below top hoses) but I will check tomorrow

This boat has had a few different owners as I don't know the history, so I am trying to fix the immediate and obvious issues as I enjoy my hobby.
Again, thanks for all the input...I am determined to try and find this gremlin with your help.

When my pressure goes down on my Hustler the line has trash/sand.mud,rust in it .also the block gets sediment in it .I blow it out and it comes back up..

rob

Wyatt
The water psi is sensed from the right side of the block by the freeze out plugs. Its a mechanical gauge with a long hose from the engine to the gauge. Try taking a coat hanger and run it thru the hose (engine side). Go to the gauge side and blow compressed air with the other side disconnected. You can get access thru the top panel in the head and you'll see the hose to the psi gauge.
I had a problem a few years back with the '88 that drove me nuts. The water intake at the gimbal housing was corroded and sqeezed the plastic hose retainer restricting flow. I would remove the hose and the 2 long bolts that hold the hose adaptor on both and compare.
Stan

you didnt read what I said usually low press indicates a blockage on the suction side on the pump or a bad pump itself, a blockage on the press side of the pump will cause an increase in pressure, the most common cause for low pressure is either clogged pickup ot where the hse comes through the transom a restiction forms due to corroion and actually squeezes the hose ( most common in salt water applications)

hence what cig1988 is saying also have seen it mant many times

Joe
What major PIA on a $1.00 part. You would think there would be a better design but I guess this is what keeps Merc and marine mechanics in business.
Wyatt,
Go for the easy stuff 1st..process of elimination my friend. I also heard of the 2" hoses collapsing from the inside causing a restriction. I personelly have not saw that yet. 1st time for everything I guess.
Stan

Thank you-I will get into it and report my findings