Merc 3.0 cylinders smoking from the plug!

[zanderman111]

Traded my old boat for an 1987 Sea Ray Seville. Merc 3.0 Alpha one. I know the previous owner tried messing with the timing for whatever reason. Well now its mine and it starts great and I was looking over the engine in neutral at an idle, after about 2 minutes smoke started coming from cylinders 1 and 4 out of the plug! I shut it off and pull the plugs and they are extremely hot!! Tip is white and clearly running too lean/hot right? Cylinders 2 and 3 are fine including the plugs. I took the 2 and 3 plugs and put them in 1 and 4 to see if i was the plugs. Same result, white tip, smoking, and extremely hot, but only on 1 and 4. Is this a timing problem? Or perhaps something with my distributor overloading those two cylinders? What would cause these symptoms? Thanks!

 

[havasuboatman]

Re: Merc 3.0 cylinders smoking from the plug!

You probably have an intake manifold leak at those two cylinders. The smoke, if it was coming out of the cylinders while the motor was running, was most likely oil on the outside of the plug burning off, or the sparkplug boot starting to burn because of the lean hot sparkplugs.
Fire the motor up an spray carb cleaner at the spot where the intake manifold meets the cylinder head. If the Idle changes when you spray, vacuum leak.

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

Yep got a intake leak. Where is the best place to buy a new one? Or has anyone ever tried making their own out of that stuff you buy at autozone where you trace the old gasket onto it and cut it out?

 

[lowkee]

Re: Merc 3.0 cylinders smoking from the plug!

I've used that DIY cork for carb gasket and cooling gasket. Not sure if it will be happy with the heat of the manifold, though. It's really an important gasket as well, since it keeps water from entering the cylinders. If it were me I'd buy a new one. NAPA may have it in stock, as they sometimes stock marine parts.

 

[rockyman]

Re: Merc 3.0 cylinders smoking from the plug!

yes i agree you should buy a new one because they have metal made into it

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

Thanks for the advice ill pick one up. Im sure it wont be too hard of a gasket to replace, but has anyone had any particular snags doing this? Any tips are welcome!

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

I got a new gasket and got it on there and all torqued down to spec, even put in new plugs. My same problem is persisting, although its not as bad as it was before. After running the boat in the water for some time, the spark plugs on cylinders 1 and 4 get extremely hot (way hotter than plugs on 2 and 3). Pulled the plugs and sure enough, 1 and 4 are blanched white. Like I noted in my first post, the previous owner did mess with the timing to some degree, could bad timing be part of my problem? Also, when out on the water and under load, the engine just wont make enough power. When trying to get up on plain, the engine revs up to approx 1/3 throttle and then just wont rev up any past that regardless of the throttle position. When in neutral though, the engine will rev up just fine, although it does seem to miss every now and then at high rpms. Are all these symptoms related to one problem? Bad timing? Bad valves? My guess is that 1 and 4 are lean enough that they arent making any power, resulting in the lack of being able to rev up when under load but I am not sure what exactly is causing them to be lean. Thanks!

 

[thannah84]

Re: Merc 3.0 cylinders smoking from the plug!

Zander, Does this have the OEM style points distributor or does it have the electronic ignition upgrade?

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

Im not entirely sure but I would say that it does not have electronic ignition. How do I tell for sure?

 

[z284u2try]

Re: Merc 3.0 cylinders smoking from the plug!

hate to say this but heat like that can be generated from a lifter collapsed or a valve not opening. I would pull the valve cover and inspect alves as someone turns the engine.
You could try to bandaid this with a cooler plug on those cyl.
You may also want to take the timing back and see if it helps. Lots of people are missled about timing that you want to advance the most as possible for best power.

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

Would a bad lifter or valve problem also be causing my lack of power/revs when under load? I am suspect of a valve problem because they looked a bit dirty when I had the intake off. I am hoping that all of these symptoms are a result of just one problem. It seems like perhaps 1 & 4 are just so lean that the engine is basically just running on 2 & 3, resulting in my lack of power under load.

 

[thannah84]

Re: Merc 3.0 cylinders smoking from the plug!

So did you set the timing back to the original specs?? Did you gap the plugs correctly? You can tell if it has electronic or points by removing the distributor cap and looking to see if it has points or a plate with the electronic module in it.

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

Borrowed a timing light. Timing was approx 12 degrees BTDC, twice what it should have been. It does have points, not electronic ignition. At any rate, the timing along with proper carb adjustments has eliminated my hot 1&4 problem. I was just using muffs here in the driveway so far. I want to take it out on the water, but another problem is holding me back. When I got the boat, the alternator was rusted out and was giving me a short constantly drawing 2 amps. I got a Delco one wire replacement and bolted it on. Fit just fine. Alligned it with a straight edge. When its running even at an idel I get horrible what sounds like belt squeal. The pulley on the alternator gets extremely hot and starts melting the belt. Belt dressing helps for about 2 seconds then just burns off. Any Ideas? I used a crowbar to push the alternator back and forth to see if it made any difference in the noise, no difference. It seems like such a simple problem but im stumped. I guess the the only thing to do is replace it??

 

[rbh]

Re: Merc 3.0 cylinders smoking from the plug!

use a straight edge to line up pulleys, then shim.
rob

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

I did use a straight edge and then put washers in accordingly. All to no avail. Made ablsolutly no difference. Like I said, I even used a crowbard to bend the alternator back and forth to see if it changed the sound. Nothing, absolutly nothing changed the sound or made any difference.

 

[rbh]

Re: Merc 3.0 cylinders smoking from the plug!

then you could have one heck of a load on the alternator, check your wiring.
oh, how secure is the unit mounted, any flex?
rob

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

It is a 100 amp, one wire, Delco marine alternator. It only has two leads on it, one to connect to the battery and one to ground. Am I missing something? The unit is pretty secure, took quite a bit of force on the crowbar to move the alternator just a little bit. I cant even really tell if the belt sqealing and the extreme heat are being caused from the same problem. Like I said, this seems like such a simple fix but I am entirely stumped. I do know that the pulley on the Delco alternator is smaller than the pulley on the factory alternator, but im not sure that this would change anything or factor into my problem.

 

[rbh]

Re: Merc 3.0 cylinders smoking from the plug!

I think with an 100 amp unit you are looking at a totaly different belt,
100 amps could really pull down the rpms if it has a full load?
check the depth, incline and width of both pulleys.
"I dont think" you can change the diameter of the pulley on the alternator,
but you might find one that will fit that uses the same belt as the original.
rob

 

[zanderman111]

Re: Merc 3.0 cylinders smoking from the plug!

I think your right. I went back and reviews the specs for the factory alternator and it was only a 55A. Guess I should have checked this before going out and buying the "new and improved" one. I just recently purchased that alternator so I can still get my money back. I have already ordered a factory replacement. Is there any risk of running the engine without the power steering pump being powered and an alternator not being hooked up? (i know nothing will charge the battery but I can take a jump pack just in case). My father was wondering if the voltage regulator or something would get messed up without an alternator being attached. I want to get this thing out in the water and see if everything else is working properly. Thanks for your help

 

[rbh]

Re: Merc 3.0 cylinders smoking from the plug!

will the pully off the old alternator fit the new one?
just a thought
rob