I've had it

[beanz2166]

So I get my boat back this afternoon, for those that don't know, I originally had a miss/"cough" in the motor. This was around late April. I took the boat to the mechanic he says I have two cylinders not firing , bam no problem, change plugs adjust timing and all is good, not so much. I put it back in the water now the boat doesn't miss all the time, just a mid (2000-2700) rpm range. So I take it back to the mechanic, 10 days ago, I get the boat back today they told me that I had some loose valves, so they fixed them up, lowered my timing (which was perfect) by 1.5 degrees and adjusted my carb. Put the boat back in the water today, and the miss is still there. The rpm range is getting smaller now its only 2300-2700ish. But that is tubing/ wake boarding speed. The miss is nowhere near as bad or as frequent as before but it's still there. What are my options. Is this something I just need to deal with or can there be another cause that the tech is missing? Gas has been drained and refueled, so it's not bad gas. I think it's just hard to fine tune because in his tank the boat runs perfect, but under load on a lake it's different. HELP,!!!!

motor is a 1996 5.7 mercruiser with gen II drive

 

[dubs283]

Re: I've had it

not sure about your issue from previous posts, but aside from what your mech did as described above have you done anything??

tune-up, filters, carb adjustment, etc...??

 

[beanz2166]

Re: I've had it

I personally haven't done anything. Cap/rotor and wires were all done at end of last season. I have paperwork showing that(boat is new for me). Other than that I haven't touched anything. Wouldn't really know what or were to start with this is my first boat.

Not bashing the mech at all. I like him, but just wondering if there is anything else possibly we missed

 

[beanz2166]

Re: I've had it

I've been doing some searches and see that replacing the coil has fixed the problem in most cases. What is a coil and where is it? Is this something I can do myself?

 

[achris]

Re: I've had it

I've been doing some searches and see that replacing the coil has fixed the problem in most cases. What is a coil and where is it? Is this something I can do myself?

Best find a new mechanic. This time, look for a MARINE/Merc certified one...

Coils are always the first suspect, and most of the time are NOT the culprit. It's usually something silly, like the timing's set wrong, or the points gap or plug gap is wrong.

Chris........

 

[john744]

Re: I've had it

I once changed my original OMC distributor for an entirely brand new Pro-Comp HEI (Delco style) solid state distributor. I then began to experience a skip similar to what you described. My brother in law auto/marine mechanic went out with me and we adjusted the timing and a few other things. He then suggested (very strongly) that I try a REAL Delco distributor cap. I had an old one that literally had a crack in it. It worked FLAWLESSLY!. Seems cheap chinese made brand new plastic distributor caps do not have the same dielectric qualities as good old Detroit ones. Just my experience ..................................

 

[beanz2166]

Re: I've had it

At this point is there anything else to do other then change the cap and rotor?
Could this cause a difference in the motor while running in the mechs tank and while running under load at the lake?

 

[alamantia]

Re: I've had it

Have you replaced the pickup or rebuilt the distributor?

 

[dingdongs]

Re: I've had it

treat to a new set of leads and what are the plugs your using as these are important.check air filter is free of gunk and if so clean it .all these things can be done yourself.

 

[dubs283]

Re: I've had it

At this point is there anything else to do other then change the cap and rotor?
Could this cause a difference in the motor while running in the mechs tank and while running under load at the lake?

your one post states that the boat is new to you, all that has been done since you've owned the boat is have a mech adjust the lifters??

just becuase the paperwork says the cap/rotor and wires are new doesn't mean they are the right ones, find a reputable shop - ask a boater friend or go to a local marina and ask around, most boat people are very friendly

have them perform a FULL tune-up, ask them what they do - should be cap/rotor, plugs, fuel filters, carb adjustment, check/set timing and idle, etc...if they are good they will LAKE test the boat and make sure all is right before giving it back to you

i would be suspect of your mech skipping over tune-up stuff and going right to a lifter adjustment with the issue you have

 

[Eric 3.7LX Alpha 1]

Re: I've had it

I keep thinking about crossed spark plug wires on this one every time I read it. Did you ever check to make sure they are correct? The firing order?

 

[beanz2166]

Re: I've had it

heres what I have done so far, new plugs, new wires, made sure everything was seated correctly and correctly routed to the proper plug. Boat seem to run a little better today, Im gonna go to NAPA and pick up a new cap and rotor. once i finish this I have no idea what else it could be.

boat idles good and the mechanic did adjust my timing and carb.

 

[Eric 3.7LX Alpha 1]

Re: I've had it

What brand of plugs did you use?

 

[beanz2166]

Re: I've had it

I keep thinking about crossed spark plug wires on this one every time I read it. Did you ever check to make sure they are correct? The firing order?

someone get this guy a beer, you Sir are a Genius! upon review once again, I found that the 6 & 8 wires were switched. havent load tested the boat yet (thats tomorrow) but hooked up the muffs and for the first time the boat fired right up without a pop bang or any other un-normal sound. tomorrow cannot get here soon enough. somehow my mechanic missed this during my two visits to him. now this leads me to this question, since my timing was set with the miss, will it matter now that everything is setup correctly?

 

[Eric 3.7LX Alpha 1]

Re: I've had it

someone get this guy a beer, you Sir are a Genius! upon review once again, I found that the 6 & 8 wires were switched. havent load tested the boat yet (thats tomorrow) but hooked up the muffs and for the first time the boat fired right up without a pop bang or any other un-normal sound. tomorrow cannot get here soon enough. somehow my mechanic missed this during my two visits to him. now this leads me to this question, since my timing was set with the miss, will it matter now that everything is setup correctly?

Glad that was it!!
It was driving me crazy reading this I kept thinking check the wires. Too easy to get them mixed up. Let us know the results after the test ride.

 

[nola mike]

Re: I've had it

Geez Eric, surprised you figured that out, what with this boat having all them extra cylinders and what not

 

[airshot]

Re: I've had it

Hate to say this but it is definetly time for a new mechanic. It should have been tested before returning it to you the first time. If all these visits have been free then OK, but if you have had to pay for them you would have been better off to see a certified marine mechanic, in the long run it would have cost you less.

 

[nola mike]

Re: I've had it

timing should be the same, but I'd double check since it was probably bouncing all over with the wires swapped.

 

[achris]

Re: I've had it

The timing signal is taken from spark plug #1, so the fact that 6 and 8 were crossed should have no bearing on the setting of the timing. That said.... I'd be checking everything that mechanic did very carefully. Then find a new mechanic....

Chris......

 

[beanz2166]

Re: I've had it

Thanks guys. Just got back from the lake boat ran like a champ all day. LOTS more horsepower and hole shot when everything is wired correctly!!!!!