AQ171C appears to be seized

"Hi guys, Welcome one and all

"Hi guys, Welcome one and all from across the pond. I have recently purchased a 1989 Fairline Targa 27 after many years of being a sailing man. However I have problems on the aging Volvo Penta AQ171C’s and looking for advice please. I have not managed to start the port engine. Firstly the starter motor had failed which was replaced, that managed to crank the engine over o/k a few times but it just wouldn’t start. Thinking I may have a flat or faulty battery I then replaced that. But now it won’t turn at all, it will not even turn over by hand with the spark plugs and starter motor removed so for all intents and purposes it looks seized. Do you think this looks terminal? I have checked the gearshift, no water in the oil and water pump impeller, even spraying WD40 into the cylinders but it is a little strange that after cranking o/k to be seized so completely in just a couple of days with no indication of any problems.
I could ask a local Volvo mechanic to look but this may mean throwing more money at a lost cause. A little disappointing as for all the expense I haven’t had any sea time as of yet."

You didn't mention if you

You didn't mention if you had tried to start it dry or wet (add cooling water to intercooler). I found my exhaust manifold was bad a few years back and water got into the engine through the exhaust valve and rusted the cylinder. Good luck.

"Hi – Many thanks for your res

"Hi – Many thanks for your response. I am trying to start this wet and boat launched and one of the service agents recently said the same thing, that water has entered the engine through the exhaust valve and rusted the cylinder. Apparently he suggested that this can happen even after a couple of days with salt water, if the engine was turning over and not starting. The other area I am looking at is the flywheel if anything from the old rusted original starter motor has come off and jammed in that area. I will persevere but it is looking expensive at the moment!"

"I would remove the spark plug

"I would remove the spark plugs and dump some diesel fuel into the cylinders and let it sit for a few days and then try turning it over. See if that helps.

Have a great day,

Rob"

"Stephen, you need to rule out

"Stephen, you need to rule out the possibility that it could be a locked up outdrive. The upper gearcase is real easy to remove, thus disengaging the outdrive from the engine. If the gears or bearings have seized in the outdrive, it could prevent the engine from rotating."

"Hi Jim, I have to admit my fi

"Hi Jim, I have to admit my first instinct on this problem was the outdrive and gearing and because of this I haven’t applied too much leverage on the front of the drive in trying to turn it over. The sump oil looks clean with no hint of water and everything else looks in good order as far as I can tell. I will probably get the boat lifted and take my time investigating which is difficult to do whilst on the mooring. Many thanks for your comments."

"Marvel Mystery Oil also works

"Marvel Mystery Oil also works wonders when trying to loosen up rings rusted rings and cylinder walls. You may want to pop the head off to 'clean' the cylinder walls before you try firing her up. Diesel / MMO most likely will free the piston(s) but you run the risk of scoring the cylinder wall(s) with pieces of rust if you do not clean them up.

You can save yourself boat loads of money by doing this work yourself. The majority of it just takes time and patience. If you have not already done so, I suggest picking up a Clymers, or Seloc manual. They are very helpful. Good luck."

"Hi Stephen,

The obvious is

"Hi Stephen,

The obvious is sometimes not so obvious !

The AQ171 is an interference engine i.e. the valves hit the top of the cylinders if the timing belt snaps, or if it is slack and can jump.

I really do hope that you have not damaged either the pistons or the valve gear, but you should check the condition of the cam belt and its tensioner as a matter of urgency.

The belt should be changed every two / three years and its condition must be examined regularly and carefully. It also MUST be tensioned properly. So many of these engines have been destroyed due to cam belt failure.

The exhaust manifold is a one piece casting and is prone to corrosion internally. This allows water into nos one and four cylinders and if you crank the engine with the water inside you can create a hydraulic lock = seizure.

To cheer you up further, the manifold is very expensive to replace and no longer manufactured by VP.

The other possibility of the engine not firing is the ICM (Ignition Control Module)is US. The unit the coil is mounted on, not the coil itself. It is unique to the engine and also very very expensive. If you decide to turn the engine into an anchor DO NOT throw the ICM over the side with it.

I am convinced that my ICM shorted out due to water getting into the engine - but not proven. Replacing the manifold and the ICM did not come cheap !

If the ICM is working and you list it (it retails new for around £400) on Ebay or on this site I am sure you would find some willing buyers !!

The other parts for the engine come under the "rare" variety so don't simply discard them either.

The reason I know some of this is because I bought the Tee Shirt.

I still run a 171C which is in farly good nick (now). They are good when the go, but they can also be a real pain in the arse, not to mention the pocket !!

Have fun and good luck.


Regards,


Doug


P.S.

Don't attempt to take the engine apart unless you know what you are doing and you have a good manual. It is quite a complex beast from the cam carrier downwards............."

"Hi Doug, thanks for your comm

"Hi Doug, thanks for your comments, I guess my fears regarding “cam belt damage” was the reason for posting. I was kind of hoping it may be something simple that I had overlooked. I have no indication that any damage has been done as there was no noise of any sort. From cranking normally one day to be completely locked up in 3 days is a mystery. The only reason I stopped trying to start the engine was because the battery may not have been fully charged. Anyway I have asked the boat yard to lift her out and put on the hard standing so I can investigate. I will keep you informed."

"Hi Stephen,

Didn't wan

"Hi Stephen,

Didn't want to appear all "doom & gloom" in my previous post.

But, if you are not familiar with the twists an AQ171 can throw at you I think it is better that you do.

Like I said earlier, I hope it is nothing serious and wish you the best of luck.

If I can help you I will - I have had some very valuable advice on this forum in the past.

Regards,

Doug

"

"Hi – Just an update. The boat

"Hi – Just an update. The boatyard has put the boat on the hard-standing and I have checked that the prop turns free with no problems, so that can be eliminated. The oil level remains the same so no additional liquid looks like it has been added. Interestingly whilst rummaging around the lockers I have found a half empty can of Easy-Start. I have heard of horror stories about this fluid as this tends to wash the oil from the cylinders and seizing the piston rings to the cylinders, so that may be a possibility."

"A free turning prop is not pr

"A free turning prop is not proof that the drive is not locked up, just proof that any lock up is not occuring between the prop shaft and the vertical shaft in the drive."

"Hi Stephen,

The prop will

"Hi Stephen,

The prop will turn free if the drive is in neutral. It would not be possible to turn it by hand if the shift mechanism was in the forward or reverse position and the powerplant drivetrain was engaged. (primary shaft connected to the flywheel damper by a spline, and to the drive upper gearcase via a splined universal joint)

You have not arrived at a conclusive answer in my opinion. Have you checked the cambelt ?

Do NOT attempt to turn the engine over unless it and the tensioner pulley look ok.

If you think it is the rings that are seized in the bores, dump 50cc of diesel fuel into each the bores via the plug holes using a syringe and let it sit for a week or two. Then connect a socket and a torsion wrench to the crankshaft pulley and have another go at turning the engine. You can increase the leverage gradually by using the torque wrench.

Before trying to turn it over, take the starter motor back out and have someone check the flywheel with a torch to see if there is any sign of movement as you apply the turning force.

Good luck.

Doug

"

"Hi Stephen

If you or anyon

"Hi Stephen

If you or anyone else is interested there is a AQ171C ICM listed on the american ebay site.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&sspagename=STRK%3AMEWAX %3AIT&viewitem=&item=190250200750

These things are like hen's teeth to get hold of !!

Doug

"

"Hi – Many thanks for your com

"Hi – Many thanks for your comments – I do agree the prop turning free is not a definitive conclusion, but one of a number of possibilities i.e. stuck in gear, that needed to be eliminated. I have checked the cambelt and tensioner and all looks o/k as far as I can see. Maybe clutching at straws and trying the simple things first as I am at a loss really because as I said before from cranking normally one day to be completely seized a couple of days later with absolutely no clues as to why."

"Stephen,
I hate to be the b

"Stephen,
I hate to be the bearer of bad news, However the symptoms that you describe are exactly what happened to me. Before you go into too much detail, take off the exhaust manifold. It is not a very hard thing to do. You are looking for the condition of the exhaust valve in #4 cylinder. I believe this will tell you everything that you need to know. I had the EXACT same thing happen to me. I have also replaced my timing belst 4 times due to belt failure. I have a LOT of experience with this particular engine. My boat has twin AQ171C's in it and when the exhaust manifold went bad I just ordered 2 of them and after sleeving the block and completely rebuilding the engine had realized that the manifold on the other motor was replaced before I purchased the boat. Again, I hate to bring bad news, but you should do this before you spend any more money. Engine rebuild with exhaust manifold is like $5,000.00 US. Good luck and please let me know what you find. I will give you all the help I can. This engine IS an interference engine and if the belt fails you Will have BENT valves. It is IMPORTANT that the sea water pump does not leak AT ALL or the timing belt WILL FAIL."

"Hi – managed to remove the ex

"Hi – managed to remove the exhaust manifold and this looks in pretty reasonable condition as far as I can see and I cannot see anything untoward in this area.
To recap, I have now the heat exchanger, starter motor, spark plugs and exhaust manifold all removed. The oil on the dipstick is like new but still the engine will not budge a fraction in either direction. I cannot see any problem with the timing belt although I guess I cannot be absolutely sure.
It looks like my fears are realised and this is an engine removal and strip down. Maybe time to rethink or call in a professional as it is probably beyond my basic maintenance skills."

"Stephen,
Just checking in w

"Stephen,
Just checking in with you. If the #4 cylinder exhaust valves aren't rusty and don't show signs of water intrusion, just to be safe, have the exhaust manifold tested. Just to clarify as well, are you trying to turn the engine from the crankshaft bolt on the front of the motor? will it budge in either direction?
Good luck. Keep me posted.
This engine is not so much the monster everyone makes it out to be. I just wish it wasn't an interference engine. Even if you bend the valves the motor will still turn. They bend rather easily."

"Hi James – thank you for resp

"Hi James – thank you for responding.
I am trying to turn the engine from the crankshaft bolt on the front of the motor and it will not budge a fraction in either direction. I have even tried to turn it from the flywheel as the starter motor has been removed. It is very odd as I would have thought even with damaged valves some movement should have occurred. My next attempt, although I know this a long shot is to remove the raw water pump as the bearing may have seized. I am not sure whether to slacken off or even remove the timing belt yet to see if that offers a clue, likewise the inlet manifold."

"If its not the raw water pump

"If its not the raw water pump, then its probably time to pull the drive off and make sure its an engine problem."

"Stephen, I agree with Robert.

"Stephen, I agree with Robert. While the boat was in the water, it was not possible to "separate" the engine from the outdrive and quickly determine which of the two was the cause of your lock-up condition. But now that the boat is out of the water, it would be real easy to remove the upper gearcase, thus disconnecting the engine from the outdrive and allowing to rule out the outdrive as the source of your lock-up. The Clymer or Seloc manual will walk you through this - it is fairly simple. Remember to drain at least half the outdrive oil first, or you'll make a big oily mess."

"Hi Jim, I do have the Seloc m

"Hi Jim, I do have the Seloc manual and it is another area I will investigate. I must confess I have tended to dismiss the outdrive mainly because of my inexperience in maintaining these drives. At least I have a plan now, so I would like to thank all those that have troubled to respond - it really is appreciated."

"I always remove the whole int

"I always remove the whole intact drive as I'm a bit of a primative. I developed a technique that allows me on average, to reinstall the whole intact drive on the boat in less than half an hour. This is way less time than the time to reassemble the upper gearcase ESPECIALLY if the upper case had ever been removed in the past and reassembled with Permatex and then pressure and vacuum test it. Just cleaning off the old Permatex is an stinker of a job, if there is any. Taking the whole drive off can be done with just one person, but a helper makes it fairly simple (A helper and a few wood blocks and a 3/8 line (one line each side of drive with a riggers hitch for a 2:1 purchase) to the stern cleat!)"

"I, too, prefer to remove the

"I, too, prefer to remove the whole outdrive. It is not a big deal to remove the helmet middle pin, the two bellows and the hinge pins (also the shift cable and the raw water hose if/when needed). I usually do the job by myself, although a helping hand is always welcome. "

"A clarification... taking it

"A clarification... taking it off is a one person job, getting it back on is what could use a helper and the aforementioned blocks and lines."

"Hi Stephen,

I have been on

"Hi Stephen,

I have been on holiday for the past couple of weeks and have now caught up with your developments.

You say the manifold looks ok - that is very good news.

Here is a simple, effective (in my opinion) and inexpensive way to check that it is sound :-

Exhaust gas channels are the inner channels and water channels are the outer. Gas and water "mix" only at the tail of the manifold.

You need a plastic two litre coke or similar bottle. A plastic cup from a water cooler and a couple of jubilee clips (one large enough for the casting circumference and the other to fit around the stainless steel inner).

Lay the manifold on its side, exhaust ports upward.

Work the plastic cup onto the stainless steel inner "gas" outlet making sure it does not split. Secure it with the appropriate jubilee clip.

Cut the Coke bottle to about a third of its original height from the base up, then drill a small hole in the bottom of it. Secure it around the casting "water outlet" with the other jubilee clip.

Close the drain tap on the manifold and connect a garden hose using a male hozelock adapter on it to the hole where the copper pipe flange was connected. The rubber seal on the hozelock fitting is just the right size for the hole - but hold it in as when the pressure builds up in the manifold it can pop out and soak you.

Turn on the water supply GENTLY - you do not need a great deal of water pressure.

The outer passages of the manifold will fill with water, as will the coke bottle. Water will exit via the small hole that you drilled in it under pressure - so beware of wet feet !! The plastic cup prevents water "backfilling" and entering the exhaust channels.

However, if there is corrosion or cracks in the internal walls of the manifold, water will enter and fill the exhaust ports.

Obviously the outcome you are looking for is no evidence of water apearing in the exhaust ports. No's 1 and 4 are the usual ones for water to appear if there is a problem.

The test worked for me - it is cheap and I believe fairly fullproof. Try it out if you wish and let us know how you get on.

If no water appears in the exhaust ports, you can breath easier and put a tick in that box.

On the subject of the outdrive removal I would also recommend the complete unit is taken off the boat. BUT I should warn you that when I went to take mine off I had a hell of a job. It had not been removed for a number of years and the universal joint splines had welded themselves to the primary shaft. When the manual says "pull the sterndrive rearwards" dont be surprised if it does not budge. I know of some guys who have had to use a land rover to pull the thing off !

Also, if your upper gear case has never been removed it can be an absolute swine to seperate it from the intermediate section of the sterndrive - mine certainly did not simply "lift off" as per the manual !

I would avoid dismantling the sterndrive if you can - you have enough on your plate.

However, once the sterndrive is off the boat you will certainly be able to establish if it is an engine or outdrive problem you have.

My money is on it being engine related.

Finally, if the cam belt and tensioner look ok DO NOT disturb them at the moment.

Best regards,

Doug.




P.S.

Have you pumped a measured dose of diesel fuel down the bores via the spark plug holes, as I suggested in an earlier post ??"

"Just checking in, I haven&#39

"Just checking in, I haven't heard how it was going. Any luck?"

"Hi James – Many thanks for yo

"Hi James – Many thanks for your interest, I have been really busy at work so not had a chance to investigate further. However because of this I managed to ask a Local marine engineer to have a quick look He managed to remove the heads in double quick time and upon investigation he has found the pistons seized in the cylinder. He has managed to free them and now we are waiting for a gasket kit to re-assemble and check compression etc. There is a fair amount of rust in the cylinders so that needs investigating as the exhaust manifold looks good, although he is going to re-check.
I will update on progress as I will let the engineer carry-on for now."