torquemaster getting enough water?

I've got a low hour stock 2001 PM 225 with a torquemaster lower. Had the boat since 04 and have had chronic overheat problems. Have spent tons with the best mechanics around with no results. Pumps, housings, poppet valves, sensors, have all been replaced, some multiple times along with powerhead removal, cooling system flushing and so forth. No alarms the 1st few times on the water but as the pump wears a little the alarms come back.
The mechanics basically came to the same conclusion that the pump is not getting enough water at lower rpm because of the ss scoops cover the intake holes. The last mechanic removed them, lowered the motor 1" lower than normal for a 21xd with the same results.
My ? is that my TM has but 4 intake holes in the casting on both sides. All the Tm that i've seen on the web have 8. 2001 was also the 1st year for the large propshaft(1 1/4) Is it a problem gearcase?

Can you provide your engine serial number?

The serial # is OT 105 261 the tag also has 2000 225 L TM on it. I'm guessing that it means its a 2000 not a 2001 year model. Thanks

Thanks!

First, let's confirm your "actual water pressures" at idle and WOT. Please be as accurate as possible.... these will be critical in trying to assist you.

Also, please look to see if you have a hose running from the TOP of the cylinder block, that connects to the poppet valve cover. http://www.bassboatcentral.com/smileys/wink.gif

There is no hose connected to poppet cover, it is plugged off. Water pressure with a new pump at idle is around 10 psi. With a little wear, maybe 2 trips to lake, pressure is back to 0-2psi at idle. At wide open with new pump maybe 15-18 psi, with wear around 8-10. The water pressure gauge needle has always been very erratic, i'm guessing because there is not enough volume or pressure to keep the poppet open(seat has been checked). The gauge is better with a new pump but still erratic. The boat has had maybe 5-6 pumps in the last 3 years maybe 12-15 trips to lake. The pumps look ok when you take them out. Not new, but not bad. No alarm at idle or easy cruising, but load the motor and the alarm will go off. The last mechanic moved transducer, speedo pickup, and lowered the motor, removed ss scoops, but the problem is back. I really appreciate you helping with this problem.

There are a TON of possibilities here... including blockages in the cooling passages, thermostats, poppet issues, adapter plate blockages, etc.

One thing you noted "pops out", however. Your engine SHOULD NOT have 10 psi water pressure at idle speed- provided you're idling at the RECOMMENDED RPM IN GEAR.

Can you verify your engine idle speed before we proceed (I'm about to send you "off the books" with a non-standard diagnostic technique, and want to make sure we're on the right track, first). http://www.bassboatcentral.com/smileys/wink.gif

It will be a while before i can get you the idle rpm in gear #, idle speed in a tub of water is 750-780rpm. In a tub, idle water pressure is 10 psi until the thermo's open, then it drops to 7-8 psi. The external head temp was 145 to 151 deg. I noticed today that it takes a while for the pump to prime, so maybe thats where i saw the 2 psi idle pressures. In the tub the water pressure guage is nice and steady but at the lake the gauge bounces violently back and forth, its always been that way. The boat has been in the shop many times for this problem, the cooling system basics-pump-poppet-thermo's-sensors-control box have been replaced some more than once. Back in march i had a well known very meticulous mechanic pull the powerhead and go through the entire cooling system. He did not find the "smoking gun" like i had hoped. The motor worked great a couple trips in march - april but the 3rd trip last week the alarm went of again. The mechanics keep leaning towards a water intake problem and want me to get a nosecone put on to help. I've always felt if you can fix the extremely erratic water pressure at speed the alarms will stop. Thanks

For starters, your idle water pressure is TOO HIGH. The poppet valve on your engine begins to open by approximatley 7 psi.... and this may very well account for your irratic water pressure AND overheating issues.

Many of these engines had a fitting the in the top of the block, and a 90 degree fitting in the poppet valve cover, with a hose running between them. This was essentially an "idle water pressure relief" circuit. It also helped to stabilize the poppet valve.

The "hose" is restricted on many models... I've found that a good starting point is 3/32" ID. This can be accomplished by inserting a smaller hose into the one you install.... ending at approximately "pitot tubing" size as a starting point.

It's critical that the poppet valve not be opening at idle speed- if it is, your thermostats cannot function properly (water is flowing through the poppet valve circuit instead). http://www.bassboatcentral.com/smileys/wink.gif

Some of these engines did alright for a few years, but over the years, the water pumps have become "more efficient" due to a migration in the driveshaft opening of the "stainless cup".

Might be worth trying this "relief tube".... wouldn't cost you a lot to install. http://www.bassboatcentral.com/smileys/wink.gif

For "low" water pressure issues- there is also a different poppet valve available. http://www.bassboatcentral.com/smileys/wink.gif

One of the thermostats has a hose that appears to dump in the midsection, the other thermostat hose goes straight to the pee hole. Is that the way its supposed to be? I'll give the relief tube a shot and see what happens. Thanks

Thermostat hose routing sounds correct. http://xs-s.com/zf/images/smile/emthup.gif

Let me know what happens when the relief hose is added.

BTW.... might also be a good idea to check the outer poppet cover gasket (make sure the cross passage is not blocked by a "distorted gasket", which will hamper the effectiveness of the relief tube you'll be adding). http://www.bassboatcentral.com/smileys/wink.gif

When adding/subtracting "restrictors"... you're essentially "aiming" for 2-5 psi at idle speed. http://www.bassboatcentral.com/smileys/wink.gif

I installed the relief hose this morning and got the pressures down 5-6 psi when thermostats were closed and 3-4 when they were open. I had to use 1/4 nipples and hose to achieve this. With 3/16 nipples and hose the psi was 6-7 (closed) and 6 (open). I'll let you know how it does on the lake when i have time to go. Thanks

Please do!

Sounds like you've got the pressures pretty close now.... and that will likely be "key" to solving your issues. http://www.bassboatcentral.com/smileys/wink.gif

Well i finally took the boat to the lake and didnt have much luck. The water pressure in gear with stats open was 2.5 psi. Running i saw 15-18 and as little as 7 depending on trim. I think i need to use a smaller relief hose. The temp gauge would climb to the overheat point like always except for idle. I notice it seems to take a long time maybe even 10 sec for the pump to prime. Guess im going to pull the pump out and take a look. And maybe replace it with a stick of TNT. (I might be a little frustrated)

I pulled the pump out and found nothing wrong with it. Looks perfect, no burnt tips, missing rubber, nothing.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by esad &raquo;</TD></TR><TR><TD CLASS="quote">I pulled the pump out and found nothing wrong with it. Looks perfect, no burnt tips, missing rubber, nothing. </TD></TR></TABLE>

Did you inspect the gasket UNDER the impeller PLATE???? Very critical!

I'm suspecting from your descriptions, that you may be pushing the "trim" limits... or your engine height may be too high.

At WOT... you ABSOLUTELY need to be able to maintain 12+ PSI of water pressure. 7 psi is WAY TOO LOW!!!!

Reading back through your post.... I would like to see a PICTURE of your gearcase- ESPECIALLY the water intakes (and their relationship to the pad of your hull with the engine trimmed level). http://www.bassboatcentral.com/smileys/wink.gif

I would also like to see a picture of your thermostat "hose routing" (a rear view of the powerhead would be great). http://www.bassboatcentral.com/smileys/wink.gif

The lower gasket has a bridge that matches the plate but not the lower housing so it was wore away but it appears that the intake and discharge sides were sealed and seperated. The engine is mounted 1" lower than paul nichols recommends for this boat and motor. The boat barely breaks 70 mph now and used to run 78 mph. This past weeekend i never trimmed high enough to see a tail maybe 40-50mph at most when the pressures dropped to 7 at on point. The last run back, between alarms, maybe 40 mph, very little trim, i had 10psi. Trim down a little and i could get better psi. Seems more inconsistant now that the relief hose is added. The last couple of trips I should have been able to see the poppet open on the temp gauge and i see nothing but a rise in temp till the alarm goes off. the lower unit is still off, so those pics will be posted later. Thank you for helping with this nightmare, i have over 4k in this problem and had no results.

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As I'm sure you already know, the gasket in picture #1 is the likely cause of your problem. http://www.bassboatcentral.com/smileys/wink.gif

The wore gasket bridge does not seal anything. The pump base does not match the gasket. The eroded part only matches the ss impellar plate. Look closely at the blue pump base, the gasket was still sealing between the intake and discharge side.