Can an engine out of timing cause this...

[Dante04SRT]

My motor has a few consistencies...

#1: It take a lot of effort to start. You have to let the starter run for 5-10 seconds continuously, and you almost have to be at full throttle. It will finally start.

#2: It doesn't idle very well, if at all.

#3: Once the motor reaches 2900-3000 RPM, it knocks/ticks very loud; ONLY under load, I haven't been able to reproduce it on land.

#4: If I go WOT, the problem lessens, almost going totally away.

#5: There is very little low end power (ie, when taking off). It takes like 30 seconds to get up to plane. Once at WOT, it will plane very nicely and feels pretty good.

That being said, I first thought, rod knock, something REALLY bad. This is what has me stumped... The motor doesn't use any oil, stays nice and cool, has good oil pressure, and generally acts normal, less a little muscle...

The fact that it doesn't idle, doesn't get off the line very well, doesn't start easily, and doesn't seem to have a lot of power, almost seems like its either the carb, which I'm sure needs a rebuild anyway, or its the timing. I haven't messed around with distributor ignitions much, so I don't really know what the first step would be. The plugs and wires are new. If I mark the cap and the distributor base and pull the cap, is there anything specific I should look for? If the timing is off, what is the easiest way to tell and what is the most direct route to fixing it. I understand TDC on a car engine, is it the same on boats? Motor is a 3.0 Merc '87.

I am really convinced that its a mix of carb and timing that is causing the knocking noise, almost like its detonating or something. Does any of this come close to adding up?

 

[bruceb58]

Re: Can an engine out of timing cause this...

So...what is your timing at?

 

[hullofalottatrouble]

Re: Can an engine out of timing cause this...

the easiest way to tell is probably with a timing light. they aren't all that expensive and you should have one anyway for annual tune-ups.. timing has been my nemesis in the past..

or you try to put cyl #1 at TDC on compression stroke and see where the rotor points and around there is where you need the cyl#1 on the cap.. could start by checking that you have the plug wires in the correct firing order.. ive messed that up in the past myself..

 

[superpop]

Re: Can an engine out of timing cause this...

I like the KISS approach, keep it simple stupid. No offense intended, but I would start with the basics. This is a very simple motor and a very simple carb. I would guess the carb is way out of whack and the timing could be off although it sounds more like an advance issue. get the manual and do a complete tune up and carb rebuild. Is the knock deep or more like a pinging. I would focus on the tune up though and the timing. Get a good factory manual and a basic timing light along with having the carb completely gone through either by you or someone who knows there way around a carb. 4 bangers are known for running rough unless they are tuned right and firing on all cylinders at the right time.

 

[thumpar]

Re: Can an engine out of timing cause this...

It does sound like it could be advanced. I would get the light on it to tell very easily and quickly if that is true. I agree with others though. Do a full tune up. If it is not running right don't use it untill you get it going like it should. A few dollars and some time could save you alot of money and alot of time later.

The knocking sound you hear is probably detonation or as most call it in the US pinging. I have owned turbo Saabs and know exactly what that is and it is not good.

 

[Don S]

Re: Can an engine out of timing cause this...

3.0L engines have a lot of problems if the timing isn't dead on. Set it right or prepare to spend lots of rebuilding dollars.

 

[Dante04SRT]

Re: Can an engine out of timing cause this...

or you try to put cyl #1 at TDC on compression stroke and see where the rotor points and around there is where you need the cyl#1 on the cap.. could start by checking that you have the plug wires in the correct firing order.. ive messed that up in the past myself..

Wires are correct. I assume #1 cyl is the most forward?

 

[Dante04SRT]

Re: Can an engine out of timing cause this...

bump

 

[Haut Medoc]

Re: Can an engine out of timing cause this...

Yes...Front.....1-2-3-4.....
The firing order is 1-3-4-2........​

 

[Dante04SRT]

Re: Can an engine out of timing cause this...

I did some reading today after work and decided that maybe, I had too low of octane in the tank... So, spent $50 and filled it with 93. Got it out on the water, and it really seemed to be running better. Could gas/octane REALLY have that much to do with my problem?

It had more power tonight and very little pinging/knocking under acceleration, much UNLIKE yesterday.

 

[ParallaxBill]

Re: Can an engine out of timing cause this...

Your timing could still be set too far advanced. Check it and make sure.

 

[thumpar]

Re: Can an engine out of timing cause this...

Higher octane can solve pinging issues with high compression motors or turbo motors but in your motor it should not be needed. I think you are advanced. I would take the suggestions and figure out what is wrong before you ruin your engine trying to find a miracle fix. Timing lights are not expensive. Go get one and hook up the 3 clips and see what you get.

 

[mike176]

Re: Can an engine out of timing cause this...

Get a timing light!

 

[Robj]

Re: Can an engine out of timing cause this...

You can run a little more advanced timing, provided the engine is not pinging. It is the detonation that will destroy an engine. So if you are running a little advanced and not pinging, that should be OK. That is how I used to run my Jeeps in the days when timing was something that you could adjust. I am sure someone else will have some comments on this. Regardless get a timing light and check yout timing.

Have a great day,

Rob.

 

[tommays]

Re: Can an engine out of timing cause this...

The 3.0 motors like to kill head gaskets with the base timing off 1 or 2 deg

i would find the correct current spec and check it while you still can


Tommays