69 Mercruiser 165 inline six rare problem done everything please help!!!

[Matt Braley]

I have learned a lot by reading all the great info here on the 165 and Aristocraft boats. I bought the wrong one, but just dug in deeper and deeper. Anyway, why am I getting no help from cylinders 5 and 6? Everything is new but the manifold. Sounds like a bold statement I know but here goes: First trip found water in oil(rusted riser dumping on cyl 6, new riser installed). But it ran like an old shaky box of crap so I yanked it and had it rebuilt at a real marine engine shop. When I got it back in it runs just as bad. I went new with the entire ignition and put a kit in my already spotless carb. It was a truck 250 so I got the marine cam and all brass plugs. What have we missed?

 

[Bt Doctur]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

compression test results, cam not timed properly,

 

[telstar1]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

manifold or block/head prob allowing water into rear cyls,would be my guess. Thats a pretty old engine.You can easily pressure check these components.

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

I have 125ish on both 5 and 6 and 4 is doin all the work. I have thought of cam timing but stopped before I questioned the oldest marine engine builder in the area on what I would think would be routine. How can I tell if the cam timing is off? My water in cylinders/oil problem seems to be over after the rebuild, new riser. Thank you for your help

 

[Lyle29464]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

I am sure you have rechecked the firing order?

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

Yes, over and over because it runs like I have the plug wires swapped. I replaced the already new plugs with new new ones and put the old wires back on 5 and 6 but nothing. I cant hear or see any leaks. Pulled the boot to make sure exhaust was not plugged up. It almost shuts off when I time it right, the sweet spot it 1 1/2 in. away from timing mark

 

[achris]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

... It almost shuts off when I time it right, the sweet spot it 1 1/2 in. away from timing mark

That sounds very much like cam timing. You are going to need to pull the timing cover off to check it properly unfortunately. The other possibility is that the cam is not the same as a standard Merc (I have seen it on a V8) and the firing order cast into the manifold is wrong for the cam. Pull the rocker cover and just check the firing order against the valve movements. You might be surprised.

HTH,

Chris.......

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

Thank you, just having something else to try makes me feel better. I'll do that in the morning. The engine has a new cam and ran similar with the old one. Instead of gaining 15 hp it just makes the engine fight itself more. I can't to have it smoothed out.

 

[Pete104]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

You make no mention of intake/exhaust manifold. 69 would be a 4 piece that would act like yours does.

 

[Lyle29464]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

ford had at least 3 firing orders but I think all the inline chevy 6's had 1

 

[dollarten]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

I have 125ish on both 5 and 6 and 4 is doin all the work. I have thought of cam timing but stopped before I questioned the oldest marine engine builder in the area on what I would think would be routine. How can I tell if the cam timing is off? My water in cylinders/oil problem seems to be over after the rebuild, new riser. Thank you for your help

I have a couple of ideas for you , one, Are you sure you are not a tooth off on the distributor installation? A inch and a half away from the timing mark would indicate that , in other words move all your plug wires back one position , This would be the same as moving the distributor. Second , you can check your cam timing by taking off the rocker cover and the tappet cover. Rolling the engine over by hand look at the number one cylinder exhaust and intake valve when they are in the overlap position . This is where the exhaust valve is stating to close and the intake is just staring to open . At this point the timing mark should be lined up on the crankshaft near or at top dead center . Now roll the engine back and forth a few degrees and you should see the tops of the valve lifters for number one cylinder just starting to move alternately from their closed position .I hope this makes sense to you and keep in mind that you are not doing this test in the firing position but, one crankshaft revolution beyond top dead center and if your engine checks out in the test , you cam timing is OK

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

I have pulled out the dist. a lot and put it in different places with no change. I line up marks on balancer and start with cyl. 1. Moving the wires back seems the same as twisting it that far, but I will try it. The cam time test is a little beyond me. I will just pull the valve cover and watch the rockers in relation to my firing order as I roll it over. The maniflod is a suspect because it is the only thing not replaced or rebuilt. Thank you guys for the ideas. Matt

 

[Fishermark]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

It could be the balancer has slipped, in which case you would need a new one. It would throw off your timing mark. If you end up pulling the timing cover, your cam and crank gear have marks on them that need to be lined up:

If you have any reservations about the manifold, it would be a good idea to replace it with a new one. Look at the area where the riser bolts onto it - did you have plenty of clean, shiny metal between the walls of the water and exhaust?

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

The balancer was loose and rattled when I got it. Following a thread on here, I drilled the center of the crank tapped it 7/16 and ran a stainless bolt up it. When I got to the engine shop he did not like this and said I might need a crank kit. Well I picked the engine up and saw my bolt still there. He said they fixed it and the balancer had to be pressed on. Anyway, with all this history(within 7 days), I can see the balancer possibly beeing part of the problem. My manifold metal was not clean and shiny but not breached or even close. The new gasket sent with the riser was too small so I made one. I would suspect that more but again I don't seem to have any water intrusion.

 

[Fishermark]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

At the very least you will want to take the gasket out that you made and replace it with the correct gasket. You can throw away any green paper gaskets that you may get and buy the Quicksilver graphite gasket. I am a big believer in making gaskets, etc... but there is a time and place for that. The riser to manifold gasket is neither the time nor place.

Also you mention the area was not clean and shiny. Did you take a flat file to it and clean the area up? That really needs to be done. Then you will be able to determine if you have good metal there or a solid collection of rust and corrosion. This may not be related to the problem you are currently having... but once you get that problem solved, you will not want to be in the same boat again... so to speak.

You want to have a good quarter of an inch of clean, shiny metal:

 

[Fishermark]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

By the way - what do you mean when you say that the #4 cylinder is doing "all the work?"

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

#4 was just a huge drop when pulling the lead. I will pull my gasket out and get the right one with better prep. A manifold is in my near future but i've just spent so much I'd like to get a ride if i can. I'm puttin this baby in the salt so such service will become routine.

 

[dollarten]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

I have pulled out the dist. a lot and put it in different places with no change. I line up marks on balancer and start with cyl. 1. Moving the wires back seems the same as twisting it that far, but I will try it. The cam time test is a little beyond me. I will just pull the valve cover and watch the rockers in relation to my firing order as I roll it over. The maniflod is a suspect because it is the only thing not replaced or rebuilt. Thank you guys for the ideas. Matt

Sorry about the cam test being a little difficult, being of a technical nature is somewhat hard to explain / understand with out visual aids . Don't worry about the bolt holding on the crank pulley . It is a good idea . The samller GM displacement engines are the only ones out of all the domestic engine makers that uses a press on balencer All other makes and sizes of engines have the balencer bolted on

 

[Pete104]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

So you don't know if your manifold is good or not? Water in cyl #5 & 6 and your worried about the balancer?
OK!

 

[Matt Braley]

Re: 69 Mercruiser 165 inline six rare problem done everything please help!!!

There is no water in the engine where it should not be. I do have the 1/4 in. or more of good metal on the manifold and a new riser. I pulled my gasket back out and will get the right one(mine appeared to have held during this unsuccessful 45 min. of test and tune/new cam break in). I tested the cam timing today by hand turning the balancer 1 turn away from #1's tdc. As I was told, moving the crank back and forth moved the two valves on #1 with only a slight movement each way. So that leaves me desperatly still needing your help. When I had the manifold off I filled it with the garden hose and did not see water in the wrong areas. Any suggestions or better test will be done in the morning. I have gas/spark/compression.