1983 bayliner capri aq125 timing

Greetings everyone,

For starters I am actually not new to The Forum however I I just finally made an account. I have been trolling the forums and getting the information I need for a few weeks now. I bought a Bayliner recently for $150. The motor cranks but would not run the interior is trashed but the transom is sound and the hull is good.
After a couple weeks worth of work I have the engine running, the outdrive runs great, the seawater system is working without leaks, the outdrive lift is functioning properlyb everything on the Boat Works. Thank you all for the help that you didn't know you were giving me.

Now for my problem. The boat runs and idles like a dream however every time I move the boat with the truck it seems like the distributor jumps a gear. This is easily remedied I simply pull the distributor move the tooth back 1 and it fires right up. The timing belt is very loose between the cam and the pulley that runs the distributor. The tensioner is keeping tension between the cam and the crank but it's not pulling the tension on the other side. When I was working on the boat the reason it wouldn't run is because the timing was not even remotely close to correct with the cam at top dead center number one the crank was about 40 degrees off and the other shaft was about a hundred and twenty degrees off. So I purchased a new belt I cleaned the pulleys with a wire wheel they weren't Rusty so I just cleaned them up and reused the same pulleys.
So before I take the front end of the engine off again my question is should there be Slack on that side or am I needing to shift the slack to between the cam and the crank so that the tensioner can absorb it?

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Crumbliss.r639 said:

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Now for my problem. The boat runs and idles like a dream however every time I move the boat with the truck it seems like the distributor jumps a gear. This is easily remedied I simply pull the distributor move the tooth back 1 and it fires right up.
There should be nothing that would cause the distributor driven gear and counter-shaft drive gear to jump a gear tooth.
The counter-shaft drives the distributor, oil pump and fuel pump. A loose timing belt tensioner may cause the belt to jump a cog, of which would throw the distributor indexing out of whack. The oil pump and fuel pump won't care!


The timing belt is very loose between the cam and the pulley that runs the distributor. The tensioner is keeping tension between the cam and the crank but it's not pulling the tension on the other side. When I was working on the boat the reason it wouldn't run is because the timing was not even remotely close to correct with the cam at top dead center number one the crank was about 40 degrees off and the other shaft was about a hundred and twenty degrees off. So I purchased a new belt I cleaned the pulleys with a wire wheel they weren't Rusty so I just cleaned them up and reused the same pulleys.
I would also replace the belt tensioner.
The automotive version is the same and costs much less than the Marine version.


So before I take the front end of the engine off again my question is should there be Slack on that side or am I needing to shift the slack to between the cam and the crank so that the tensioner can absorb it?
I may not be understanding you on this one!
The tensioner controls the slack on the return side of the belt.... meaning that it places tension against the belt as it leaves the cam pulley and returns to the crank pulley.

Take note as to how the tension spring provides pressure to the bearing/roller unit.
Tighten the center bolt only after you have achieved adequate belt tension.
You may need to start engine, shut off, and re-check/re-tighten!


Lastly..... note that the OHC 4 OEM ignition distributor flyweights and return springs can become rust compromised.
When you set BASE advance, also look at the progressive and total advance as per OEM specs.
Your OEM work shop or service manual will give you the specs for your engine model.

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RicardoMarine said:

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Take note as to how the tension spring provides pressure to the bearing/roller unit.
Tighten the center bolt only after you have achieved adequate belt tension.
You may need to start engine, shut off, and re-check/re-tighten!

thank you that is exactly what I missed. Totally and completely missed the sections on tightening the tensioner proper way. I went back and looked at the manual again and sure enough this is my problem thank you so much I appreciate it.
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Richard

Crumbliss.r639 said:

thank you that is exactly what I missed. Totally and completely missed the sections on tightening the tensioner proper way. I went back and looked at the manual again and sure enough this is my problem thank you so much I appreciate it. Richard

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You are welcome.

Just make sure that you not only set BASE advance, but that you also increase RPM (as you strobe the timing marks) so that you can see what the system is doing progressively up to the "full in" RPM.

You should be seeing a linear advance curve, starting from the BASE value progressively up to the "full in" value (4,200 rpm).
You do not want to see the advance coming on too early.

Here is a copy of the OEM specs:





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Well, distributor and cleaned everything up checked and made sure that the advanced was working everything looked good put it all back together I think that the timing shaft it runs the oil pump and the distributor is off one tooth because I have to go to the extreme to get it in the right position for timing if I move it one tooth then I have to go to the extreme the other direction.
We took the boat out on the lake today did some trolling opened it up got it going we were doing about 22 miles an hour at 4000 RPMs. We're having some fun until...

The number 3 cylinder is dead. It happens suddenly without warning. I managed to limp it back to the dock. I pulled a spark plug and checked compression and I have great compression on that cylinder I checked to make sure I was still getting spark getting spark on that cylinder so I'm thinking I might have a frozen or broken or bent valve on the number 3 cylinder. Is there any way you can think of said I can check that without having to pull the head off.

On the plus side when this happened I got a closer look at the engine and realized one of my freeze plugs was spewing water so honestly I'm looking at probably having to do a full rebuild of the engine. So the final question I have is where is it inexpensive place to purchase a full engine rebuild kit for this engine. Aq125

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Crumbliss.r639 said:

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I think that the timing shaft it runs the oil pump and the distributor is off one tooth because I have to go to the extreme to get it in the right position for timing. if I move it one tooth, then I have to go to the extreme the other direction.
Notice the distributor hold down system, and notice that the arm off of the distributor housing is slotted.
The slot gives you a very limited range in which to adjust the indexing of the distributor housing.

When the counter-shaft's cogged pulley is indexed with the crankshaft and camshaft pulleys correctly, the counter-shaft drive gear and the distributor driven gear align correctly, allowing the adjustment slot to give you a correct ignition timing adjustment.

I know that the two gears cannot jump a tooth.
I also know that if the timing belt was to jump a cog (on the counter-shaft pulley), it would definitely change the distributor's indexing.

In other words, it is imperative that the timing belt be indexed correctly with all three cogged pulleys, in order for the adjustment slot to allow for correct distributor housing positioning!


The number 3 cylinder is dead. It happens suddenly without warning. I managed to limp it back to the dock. I pulled a spark plug and checked compression and I have great compression on that cylinder I checked to make sure I was still getting spark getting spark on that cylinder so I'm thinking I might have a frozen or broken or bent valve on the number 3 cylinder.
If the #3 cylinder pressure is great, then you do not have a valve issue on #3.

Is there any way you can think of said I can check that without having to pull the head off?
I guess I'm not following you!
You say: "number 3 is dead" then you go on to say: "I have great compression on that cylinder"



On the plus side when this happened I got a closer look at the engine and realized one of my freeze plugs was spewing water so honestly I'm looking at probably having to do a full rebuild of the engine.
The AQ125s were all fitted with Closed Cooling Systems.
If you are seeing water come from a casting core plug hole, something is very wrong!


So the final question I have is where is an inexpensive place to purchase a full engine rebuild kit for this Aq125 engine?
This company sells a complete long block. They may also be able to provide rebuild parts.
http://remanufactured.com/Inboard_Marine_Engines.htm


By the way, any of the Volvo Penta single OHC 4 cylinder engines will work for your boat....... AQ125, AQ131, AQ140, AQ145 etc.
The over-all drive reduction (2.15:1) is the same for all of these engines.

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