*** trim problem 228 Mercruiser ***

[blairw]

I have a 1980 228HP mercruier I/O on an 18' cobia. Last month- outdrive started going down very slow. it's fine coming up 4-5 seconds. someone said it was the trim pump -so I replacing the trim pump head, I checked the pump on the bench- solenoids make the motor & pump go forward then reverse and it seemed to pump fludid through the tubes ok. However after reinstallation, it goes up fine but in the down position...it makes a slight gurgling sound and still slow. I tried to purge the lines at the vucuum side of the pump...and when u losten the fiting...fluid seeps out and the outdrive comes down. But it's still as slow, like it's trying to pull but never catches? <br /><br />Someone said it might be the check valve assbly on the back side of the engine that keeps the outdrive from kicking up. After removing it- and cleaning and a simple air test on the bench...the valve does seem to open and shut. it seemed ok except now somehow after I reinstalled it...and put the linkage bracket right on top with the same 2 screws ...now I cant trim up while going forward at speed. It appears that the check valve is open and the pump wont pressure up to allow trimming at speed? I tried moving the valve in small increments to the notches on the valve top?- no change throu out the full range of adjusments. In desperation I pulled off the linkage bracket and manually moved the valve while at speed and then it closes and will trim up. <br /><br />so now I still have a very slow outdrive going down, it kicks up in reverse (and has always since I got the boat this spring) and........I cant trim the motor while in forward gear???<br />help!!<br />Boater Blair <br /> bytheseaboy@bellsouth.net

 

[Ralph 123]

Re: *** trim problem 228 Mercruiser ***

It may be that your trim cylinders (rams) needs to be rebuilt. There is what they call a bearing inside that will get corroded/dirty/burred and prevent the ram from retracting (or make it retract slowly). You need to disassemble and ream out the bearing. While you're there you might as well install the rebuild kit (new o-rings, inner sleeve, etc.) - with a 1980 you're at the time this starts to happen (I have a 79 and started experiencing it last season)<br /><br />To confirm, remove the rams from the outdrive and and leave them attached to the gimbal ring. Then run the pump up and down - if they both extend and only one retracts you'll know for sure that's your problem. If they both don't retract it could still be your problem and both rams need rebuilding...In my case it's always been one at a time. Another way to test them is disconnect them and disconnect the lines and pull and push them by hand - if can't push them in by hand that's the problem<br /><br />You can see what the rebuild kit looks like here and the genuine Merc kit comes with instructions - not sure if the Sierra one does:<br /><br /> http://www.mercstuff.com/trimcylparts.htm

 

[blairw]

Re: *** trim problem 228 Mercruiser ***

Thanks Ralph. I'll try testing the Rams today. But my second problem (not trimming -up at speed) I somehow feel is my fault and may be Linkage related. After I reinstalled the check valve assby back onto the mounting bracket, and bolted on the throttle cable arm. It appears that i have to find a way to adjust the range of motion so the check valve remains closed while the throttle is past neutral in forward gear. you know...I took such care when I pulled the check valve off to lay the cable arm to one side, and never did any adjustment, yet when I reinstalled it...now she insnt right??<br />Kinda like like a woman.

 

[Ralph 123]

Re: *** trim problem 228 Mercruiser ***

You may also need to adjust your trim limit switch - read this:<br /><br /> http://www.mercstuff.com/trim_limit.htm

 

[blairw]

Re: *** trim problem 228 Mercruiser ***

well the rams are problematic. both extend fully. only one slowly retracts and that only half way by itself. so i pulled them both off and cleaned, wiped etc. didnt see anything like a bearing only a item bolted in that had several spall springs held down by a cap washer.

 

[Ralph 123]

Re: *** trim problem 228 Mercruiser ***

You do have the rams that have two hoses going to the aft (transom end) correct? The ones shown at the top of that mercstuff page I sent you right?<br /><br />If so, you need to pull the whole ram out of the housing. In there you'll see this (see pic) it rides on the ram. This is what they call a bearing and what needs to be cleaned, new O-rings, etc... Note the o-rings are off this one. Note how the opening gets chewed up. Also note how the inner sleeve begins to corrode and should be replaced too.. hope this helps<br /><br />edit: on newer rams, I think this "bearing" has been integrated into the end cap.<br /><br />

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[blairw]

Re: *** trim problem 228 Mercruiser ***

Dear Ralph.<br />Thanks so much for your guidence! It worked!! I cleaned both rams out, and the sluggish one i used steel wool and wet sand paper to remove that corrosion and smooth out all the moving parts. It works well now. It still takes about 10 secs after I press the down button to "catch" then she falls like a rock! Perhaps some air is still in the lines preventing it from "catching" right away??<br /><br />Now i'm going to see if I can address the 2nd problem; not being able to trim up while running at speed. I've tweeked the reverse check valve that is the culprit...so we'll see? I don't know what else to do ?<br />Thanks<br />Blair

 

[Ralph 123]

Re: *** trim problem 228 Mercruiser ***

Excellent!!!!<br /><br />Make sure the vent screw on your pump is open so air can escape while it bleeds - you need to be sure it is backed off a few turns from all the way in. With the rams retracted all the way, fill the pump with fluid, then run the pump up and down a few times. I also crack the lines afterward to let any air escape. You should see just fluid (no bubbles). Then, retract all the way and top off the fluid.<br /><br />You may not be able to trim up at speed because the rams are leaking (need O-rings replaced) The force of the prop at speed is causing the seals to fail and allowing the rams to collapse back in... buy the rebuild kit - those rams are old and need new seals.<br /><br />[edit] PS - be careful if those lines haven't been cracked in a while. You can easily round the nuts if you try to use just a standard 3/8ths open-end wrench. If you can, get your hands on a 3/8ths flar nut wrench and use that. They look like this:<br /><br />