Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER Mod

[tampa boater]

Hi There - Saw the Sticky on the bulletin related to "Drive leaks down, trim system does not hold pressure" - Bulletin 44-5-2A. It indicates it applies to "All DP-290 with Power Trim", however the pump in the picture shows the later model and I have the "earlier model" as pictured in the 2 attachments. My system is exhibiting same behavior.

Does anyone know if the procedure will work on the earlier model pump - and, if so, where are the up/down valves located?

edit - just to clarify - I have outdrive model Volvo DP-290a. They year I believe is 1990. The engine is V8 5.7L Volvo around year 2000 on new block. And my symptom is drive leaks down quickly with no external leaks (new seals installed) - don't know if it worked properly prior to new seals - was leaking when I purchased the boat. Drive will not trim up when under load at planing speed - though the electric motor does engage (I can see voltage meter go down but trim angle does not change on gauge) - i.e. works when not under load / at idle but sinks down quickly and the internal leak / bypass is such that it won't trim up at all under load at speed. It will trim up in forward at slow speed but sinks quickly all the way down within a few seconds.

Thanks! - Steve

 

[tampa boater]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

bump?

 

[Don S]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

Since it's a completely different type pump, I sure don't see how the fix could be the same.

 

[RRitt]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

Your valve body is leaking down because the internal rubber is old. Your check valves need to be replaced. If the regulators are renewed at same time then the vb is good to go another 20 years. The original material was buna. If you use viton check valves seals it would not be unreasonable to expect 25-30 years from a rebuild. I rebuild them and list on ebay. There used to be another outfit from Tampa that rebuilt them. A lot of force owners have used briggs and straton carb kits to rebuild their check valves. I have gotten a couple sent in for repairs and the briggs part is holding up very well. It is clearly a valid solution. Just be careful not to damage the aluminum housing when you pry the check valve open. clean with lacquer thinner, scuff the steel shoulder lightly with #320, and assemble with red locktite. Don't take the gearplate off. It is difficult to get it working right again after you do that. I'm not sure what, if any, other options exist for oem.

aq290 can use a Force valve body. Just plug the extra ports. There is a cheap asian product on market for $100ish. But it is, as expected ... cheap. The aftermarket will have a 3-7 year life expectancy on 30-90HP. On bigger engines I would not make any guesses. Your old valve body is the best. If you plan on keeping your boat then rebuilt oem is really the best choice.

you trim motor should also start acting up soon. It has Buna seals too. the buna is getting old and moisture will be creeping inside. The chinese aftermarket motors are decently good - and cheap. $80ish. Get aerosol plasti-coat or flex-seal and coat the motor before installation and the asian motor for volvo AQ290 is a "best buy".

 

[tampa boater]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

Thanks RRitt! Great info! I just want to be sure I am "prying" the right part... The check valves are on either side behind the internal snap retaining rings, correct? As in this pic? ----->>>> If so I am having no luck removing (I took the pic before I removed the ring).. Any tricks? Thanks - Steve

 

[RRitt]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

that looks like a standard force or volvo valve body. The volvo is same as force except that only two of the ports are active. You can use a force VB on volvo by using 3/16" brass brake plugs from NAPA and just plug up the unused ports. Unfortunately going the other way isn't as easy because the force has SS plumbing and there is no room to use a "tee" fitting.

At any rate -
a) you get plugs out by running the pump. Use a punch to gently drive the plugs in 1/16" and then remove snap rings. run the pump and one side or other will come flying out. sometimes with spectacular results. I had one fly clear across the shop and make a resounding smack on other wall. Be careful not to lose snap rings. They need to be SS and cost $1ea in bulk. I've never seen them available for onsey-twosey purchasing. You may not need $25 worth of snap ring inventory.
b) the only successful instances of home repair I've ever seen cannabalized the small oring from a briggs carb kit. Hunt force forums for the thread.
c) the chinese aftermarket valve body is only $90. The aftermarket VB is not up to the same standards as original. It uses super cheap material grades and has shoddy machine tolerances. About 10% of them have leaks and drips from factory. But - they do work. Fixing your original is better. you'll get at least 10 years out of the briggs fix. You'll get maybe 3-5 from the aftermarket.

 

[tampa boater]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

Thanks! Running the pump worked on one - then pushed out the other after removing the 'shuttle valve'. Then heated in boiling water and removed the 'cap' from the valves with pliers while protecting in a cloth - wiggling back and forth on cap while holding the larger part of the valve in vice grips (also wrapped in cloth). One seat was gone completely (literally missing) - the other only half was there and it came out in brittle small pieces...ended up ordering mercury pn 820719 valve seat - based on a tip from clanton on another forum. any experience with that? Is as good as the briggs carb kit valve seat? thanks again for all the great info!!

 

[RRitt]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

IDK. I would think that ti should be as good or better than the briggs. When I first saw the briggs i was afraid that if it changed shape under heat and pressure that it may not seal. It looked like if it was pressed into the full volume of needle then it would not be tall enough to have good contact. The few briggs that I have stumbled across have held their shape. Considering the problems with gasahol, water, and buna ... they may even be witon.

The mercury p/n may be for the whole poppet. Their seal is more like a poly. It is very durable. better than buna rubber. Viton is a miracle rubber though. it resists harsh chemicals, salt water, heat, and tearing all at same time. On the one hand, viton is better than poly. On the other hand the merc poly is an exact fit. Not a clear winner one way or the other .... i think I'd pick the merc.

 

[tampa boater]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

Thanks again RRitt!! So turns out replacing the check valve seals improved it but now I (still continue to) have another issue. The unit will not trim out / up under load. Seems to me it's bypassing via the up circuit relief valve. See pics via the link below also one of them here ----->>> . Does anyone know if there is supposed to be a seal on the valve? It's the little part in the pic that is show both in and out of the seat. Seems this is an old prestolite pump and I cannot find the parts diagrams anywhere... Thanks!

https://picasaweb.google.com/107931...authkey=Gv1sRgCMmCnYTItrHmpwE&feat=directlink

 

[RRitt]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

plug all the ports except the "up" port. hook up a hydraulic pressure gauge and run trim motor. it should read around 2000psi while motor is running and hold on about 1800psi after you let go of switch.

the running pressure is determined by the valve in picture above. adjust as needed.

after the motor stops spinning, the check valve holds pressure. if the gauge drops without any external leaks then the check valve (aka manual release plug) needs rebuilding.

 

[tampa boater]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

THANKS RRit! I forgot to mention I did connect a gauge (0-5,000psi) and it only showed 200psi or so on the up circuit - running the motor in the up direction. The relief valve does not seem to be an adjustable type (not threaded). Just a spring and a valve. My thinking is where the valve sits in the seat should be a seal that has deteriorated and is missing (like 1 of the 2 check valve seals did).... ??? i.e. it's currently metal to metal. Thoughts? Thanks! - Steve

 

[RRitt]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

THANKS RRit! I forgot to mention I did connect a gauge (0-5,000psi) and it only showed 200psi or so on the up circuit - running the motor in the up direction. The relief valve does not seem to be an adjustable type (not threaded). Just a spring and a valve. My thinking is where the valve sits in the seat should be a seal that has deteriorated and is missing (like 1 of the 2 check valve seals did).... ??? i.e. it's currently metal to metal. Thoughts? Thanks! - Steve

the spring should compress about 5/16" and have at least 1200psi. The thicker regulator spring goes on the port away from the very tiny spring. Not all valve bodies have dual regulation. Most engine makers went with less costly single regulation after 1988.

If springs are proper and you still only get 200psi then you need to replace valve seat, gearplate, and/or regulator springs. If such is the case then your best bet is to either look on ebay for the Chrysler Force rebuild service or replace with the cheap chines VB. There is only one factory and any aftermarket valve body for under $200 is identical to any other. The quality is poor and the lifespan is short. The chinese VB should be bought with the idea that it will need replacing within 3 years.

 

[jfalco]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

i had this same problem last year and posted it here 2 times with no response at all, i ended up buying a new pump/ motor (aftermarket) and im not happy with it, does not work on plane, having your unit rebuilt its your best choice, where were you guys a year ago, i threw my old unit away because the replacement worked perfectly out of the water, this advice is very helpful to me buts its a year too late for me, good luck tampa boater.

 

[RRitt]

Re: Drive leaks down, trim system does not hold pressure-Model 290, PowerTrim EARLIER

i had this same problem last year and posted it here 2 times with no response at all, i ended up buying a new pump/ motor (aftermarket) and im not happy with it, does not work on plane, having your unit rebuilt its your best choice, where were you guys a year ago, i threw my old unit away because the replacement worked perfectly out of the water, this advice is very helpful to me buts its a year too late for me, good luck tampa boater.

i've been rebuilding prestolite trim pumps since 2003 under the category of Chrysler Force. The aftermarket motors are pretty decent. The brush quality is poor but the oil seals and winding chatter is better than oem. If they did a better job with seals and rustproofing then they would be as good as original. But the VB just plain suck. The aluminum is like pot metal, the rubber seals are pitiful, and the tolerances are sloppy. In one case, they don't even use the right size of o-ring. The best thing for cheap VB is for emergency use and then swap it back to oem as soon as possible.