Pmax Issues

[JR]

I have two problems with my high time '98 PMAX 225 SS.
The poppets are sticking at idle-only zones and causing it to overheat until I rev it a little more and pop the poppets. How hard are they to change? The pump is having to get up to 28 PSI to open them.

Problem # 2: My alarm box is sounding the fast 1 second beeps after a couple of minutes running. It is driving me nuts.
I have checked an my oil reservoirs are full and my oil pump is pumping. I disconnected the water in fuel sensor too.

Would you guess it to be the alarm box or the pump rotation sensor?
Both were changed 5 years ago.

BTW, I am keeping the oil injection since I have gotten over 1500 hours on two powerheads and am not willing to premix, as much fuel as I use.

 

[David Lanham]

JR

The Poppet flows water as a function of engine RPM/water pressure. It does not open as a function of eng temp. It basically free-flows water at 1,500 RPM and up according to the shop manual.

At idle speed, the T stats controls engine temp.


1. Check each hose (down stream) coming off the T stat housing for blockage ie, small pebble. On mine once, a small pebble got lodged down stream of the T stat, just inside the P discharge nipple. Ran hot at idle and would only cool if I rev up the motor or got on plane.

2. Weak water pump impeller; doesn't flow enough at idle.

3. T Stats are stuck closed from all the salt water time.

Not sure on your alarm issue.

 

[JR]

Thanks, I will check it for obstructions. My water pressure gauge is at almost 30 PSI at idle. When I slightly punch the throttle to about 2100 RPM [too fast for no-wake] the pressure spikes and then comes down to 22 PSI and my engine cools off. That is why I though the poppet was sticking. My normal pressure at WOT is 30 PSI.

 

[AllisonboatsMS]

wow my wot water pressure is only about 12 psi but i always have a steady stream out the hole.

 

[RedAllison]

JR has your SS always idled with that much pressure? Mine NEVER had pressure and never peed anything out the peehole either, all the good engine guys told me that many times the SS motors were dumping so much water down the mid that they just didn't pee much or have much water pressure at idle. I'd say you HAVE to have some sort of obstruction inside. Like David said, with all the long distance saltwater (as well as stump jumpin you've done a time or two) you might have some Tstat problems. Sorry, can't help ya with the alarms. Since I don't have my SS anymore I don't have manuals or anything to tell you what beeps mean what.

I woulda NEVER believed you have put that motor through all you have and did so WITH the factory oiler!!! :cuss
RA

 

[David Lanham]

I read more info in the shop manual:

Normal Idle water PSI is: 1.0-3.0 psi. If it's higher than 5 psi then inspect for plugged poppet valve by-pass passage or tell-tale.

Also says to inpsect poppet vavle seat for other coolant problems.

 

[whipper]

If the magnet off your pumps gear is falty check your zinc make sure its not coroded. Deteriorating anoids can cause lots of strange ground problems. Im not sure about demagnitization though? My dad left his boat at his warf year round and i know he always had strange problems because of anoid streangth after awhile. Sounds like an obstruction or time for a water pump kit and new t-stats. I have a like new worm gear and water sensor i can send you if you want to try replaceing those? Heck you can have the whole oil injection assembly if you need it.

 

[Hotprop]

A faulty switchbox will also make the alarm sound !!

 

[JR]

I changed the thermostats 3 years ago just due to hours in service. The poppets are original.

I am going to drop it off at Curtis's tomorrow so I can have it back for the weekend.

Quite possible it is the switchbox since it runs for several minutes before it starts chirping.

 

[AllisonboatsMS]

had something kinda weird happen to me today..motor ran fine and had good pressure.. but got reasl hot after a long run at cruising speed....after i slowed down it cooled off.With it being 100 degrees outside was it just not pumping water fast enough at 40 mph?

 

[whipper]

if you go faster than that say around 60 or 70 does the temps come down? I know mid range or slower like 40 is an awkward speed and mine doesnt like it at 40 very much for temps. i think mine needs a new impeller as its been a year! Just to busy working on other motor stuff but going to change it on the weekend.

 

[JR]

Mine runs 180+ at crusing through WOT and used to come down to 160 at idle.

 

[cdaallison]

JR, I have a 99 225 promax 15 inch mid. I hardly piss water at all it pisses a little ,spurts a little, and I was concerned.My water pressure has always been strong fairly low at idle and incrimentally higher till I am at 30psi at wide open. My temp is very constant at 140 to 145 and lake water temp is usually around 70. I am about positive there isn't an abstruction and wondered if the 15 inch mids run a little more pressure and less pee. Mike

 

[JR]

My Tech found the poppet was full of seaweed and was restricting the flow at idle. Now it runs good at idle.

I still have the beeper going off. We checked the oil float, changed the Oil module, checked the water-fuel sensor, checked the output voltage to the coils [looking for a bad switchbox]. We are going to check the oil rotation sensor Monday and if that doesn't do it he is going to get another oil module since he has had bad-out-of-the-box from Merc before.

Curtis is "Hating it" on troubleshooting my engine since the Merc diagnostic tester won't work with my Brucato ACU. The ACU is still woth the extra effort anyday.

 

[JR]

We finally found out the beeper problem was due to an internal rub thru inside the wiring harness. I am having a new harness installed since mine is 10 years old, exposed to salt and has over 1,500 hours on it. They can wiggle the harness inside the boat and the beeper goes quiet.

 

[JR]

The harness failure was right at/inside the large round engine side connector, not the boat side of it, like I thought. This could be an issue for those of us that don't know how to slow down in very rough water. The heavy connector flexes the wire due to inertia.

 

[allisonjr]

Glad u got ur pro fixed!!!

 

[brotherxb03]

I'd unhook that oil injection. Of coure with that many hour's on it,I'd take it apart and ring it with new seals,bearings,rod bolts before you loose it,unless your ready for a new green motor. Might need to be over sized with new pistons also.

 

[JR]

The new Powerhead only has about 500+ hours on it and compression on all 6 was perfect with no scuffing.

I am keeping the oil injection since with yearly inspection it works flawlessly.
Curtis says as long as I keep up my yearly maintenance the O.I. should never have a problem. BTW I went ahead with a new alarm module and pump rotation sensor even though the others were still good. The gear drive was good too.
The only issue I have with my "Timex-Promax" is with driveshaft corrosion on the 15" midsection. Curtis and I were talking about a non HP stainless driveshaft.....

 

[msethsmile]

If your corrosion on the d-shaft is around the impeller area, it may cause leaks. Two tricks, put extra gasket below, that will raise o-ring seal enough to stop leak. Also, NAPA sells a sleeve that goes over the shaft at the impeller area, slick as can be.