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AQ125AVP270 Replacement

D

dr_velocity

Member
"I know it's been discusse

"I know it's been discussed, but I didn't see recent threads on it.

Boat: 1982 Bayliner 19' Capri
Engine: AQ125A
Drive: Volvo 270

I fixed the wiring in the boat this afternoon only to find that the engine has some serious problems. When it was running, it consumed oil at an alarming rate. Now, the start cranks, but the engine is not turning. The timing belt does not turn. If I add tension to the timing belt, it will turn and you can hear the crankshaft and valvetrain start to rotate and the engine fires.

The drive works for the most part. There issues with it and it may be time to replace it as well. The power lift shaft is sheared and not connected to the drive anymore. The shift-lock (device that locks the drive in place when forward or reverse) is either broken or in serious need of adjustment. The hydraulic lift motor is on it's last leg.

The engine did die conveniently at the end of the season, so I'm in no hurry to get it going again. What I'd like to know are my best options:

• Rebuild engine and drive
• Replace engine and drive
• Sell

The boat itself is in decent shape. It needs a bit of TLC, but it could be brought back into excellent shape for under $100.

I'm pretty competent with tools, so I'll be able to do the work myself. So, what are your opinions on my options? If suggesting a replacement engine/drivetrain, tell me which engine and drivetrain and what all is required to make it work in the boat."
 
"Hmmm, in my reply to you in t

"Hmmm, in my reply to you in the other thread I thought that the timing belt coulf be slipping; but since you mentioned in this new one that the engine starts when you put tension on the timing belt, I stand corrected, for a slipping timing belt cannot be your problem.

If you have so many problems with your current package, your cheapest option might be selling the boat and getting another one with the power train in better condition. Having said that, you may want to shop for the opposite: a boat with the hull in bad condition with a decent Volvo Penta power train. Most 270, 275 or 280 drives will be compatible with your current transom shield; and the ones that are not (like in the case of the transom shield with double bypass for GM 305 and 350 engines) will come with a transom shield that will bolt directly in your current transom hole. If you go for a 290 drive, you will have to cut a larger transom hole, as the transom shield is larger than the one you have.

If, however, your problems are limited to your curent engine, I still would go for a B21 automotive engine (Volvo 240 76-82) and marinize it."
 
"Well, the engine doesn't

"Well, the engine doesn't start per say, but you can hear the occasional cylinder fire while it's turning.

When you say marinize, I'm guessing that includes an entirely different exhaust manifold. I suppose a turbo'd B21 wouldn't really cooperate in the marinization process."
 
"Adam, now I am getting a bit

"Adam, now I am getting a bit confused. I cannot understand how the crankshaft can turn if you put extra tension on the belt. What would normally happen is that the crankshaft turns when the starter engages, but not the OHC (overhead cam) if the timing belt slips. This was my first diagnostic in the previous post, and as I said it is easy and relatively inexpensive to fix. Also, keep in mind that even if the timing belt slips, the circulating pump and alternator would also move when cranking the engine. You may want to verify whether or not this is the case before discussing this further.

Marinizing means transplanting all the marine parts from your current engine into the automotive engine, which must be naturally aspirated. The marine parts include the starter, the alternator, the mounts, the intake manifold and carburetor, the fuel pump, the exhaust manifold, the cam, the circulating pump, the raw water pump, piping, distributor, belt cover, water expansion tank (I hope I did not forget to include anything major)."
 
"Maybe this will clarify...

"Maybe this will clarify...

While running the starter, the timing belt does not turn at all. Neither pulley that the timing belt runs around turns. When I used the but end of a screw driver to push in on the timing belt, the timing belt and both pulleys turn and you can hear the engine occasionally fire."
 
"Well, as El P said, the timin

"Well, as El P said, the timing belt is slipping. Pull the water pump, alternator belt, mounting plate and heat exchanger to inspect and repair the timing loop. Follow Seloc instructions for aligning the three cogwheels, installing belt and adjusting idler. However, if what you said is literally true, that none of the three cogwheels is turning, go to plan B.

Alternately, pull the outdrive and gut the engine bay except for mechanical and electrical controls. Save marinizing parts or other goodies such as the sending units. Shop for replacements of same type engine and outdrive. Either go automotive or shop EBay. Inspect transom before going ahead with purchase."
 
"To me the problem with the mo

"To me the problem with the motor is not the timing belt, but rather the high oil comsumption. Fixing the timing belt won't help with your oil conspumtion. Get an automotive engine and then marinize it.

Have a great day,

Rob."
 
"If the problem with the oil c

"If the problem with the oil consumption is due to the oil pan leaking (pretty comon) or to a faulty crankshaft seal, that also would be an easy fix. And if the motor needed re-ringing the pistons or a valve job, that wouldn't be the end of the world, either."
 
"Thanks guys, you're a gia

"Thanks guys, you're a giant help. After thinking about it a bit, you guys sound right on the money with the timing belt loop. I can verify that the two visible pulleys aren't turning, but I can't tell you what condition the gear set is in. It makes an awful lot of sense that the gearset is worn - the teeth aren't grabbing until extra tension is added to the timing belt.

My original guess to the oil consumption was do to leaky oil pan and I'm guessing this is still the case. I haven't had the time to do a leak down test to rule out other variables as I have plenty of my own projects.

I think pulling the engine and stern drive are in order as the season is over and we have plenty of time to fiddle with things and find out where we are at.

Again, thanks for the help guys."
 
"On a side note, I posted the

"On a side note, I posted the exact same thread on the iBoats forums and got one bunk reply (someone trying to tell me that you can't test voltage when the system isn't under load...). People here seem much more knowledgeable."
 
"Adam, I also go to Iboats, an

"Adam, I also go to Iboats, and there are many knowledgeable people there, who are willing to help as well as at this site. I do feel this site has more expertise specific to Volvo Penta drives and engines. I think the advice you were given is checking voltage under no load is one thing, but under load is another. So checking voltage on a circuit while it us under a load also provides valuable information. You may have 12 volts at a starter without any load, but that voltage can drop significantly under load due to a poor connection, corrosion, faulty starter etc. What no load tells you is that there is voltage, what it tells you under load is the circuits ability to supply the required amps and volts.

Have a great day,

Rob."
 
"Rob,

Yeah, I understand t

"Rob,

Yeah, I understand that perfectly - I've got a degree in physics with plenty of electronics circuitry experience as well. For the problem I posted (no voltage to anything), the load was irrelevant. So, the response I got over there really had no bearing on my problem. There are plenty of knowledgeable people over there, yes, but I generally get quicker and better answers over here - you're probably right on the money about the Volvo Penta correlation.

We've decided to pull the engine and start tearing it apart to see what needs work and whether a replacement is in order."
 
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