87 90 hp Mercury - No spark

[Laddies]

Re: 87 90 hp Mercury - No spark

Don't trust the mercury switch, if it starts with it diconnected and you hook it up and it stays running but then won't start later try to diconnect it again and try to restart--Bob

 

[harwich]

Re: 87 90 hp Mercury - No spark

Bob,<br />It did start repeatedly last night with the mercury switch connected but it would not start this morning, of course it did not start yesterday morning with the mercury switch disconnected.<br /><br />Temperature this morning was 69 degrees when it failed to start. I took the following readings this morning.<br /><br />(My flywheel appears to be a cast one)<br /><br />blue to grnd 400 - 1000 ohms. (this is the wire that I can not get a good reading on because it flashes for a second and then shows open)<br /><br />red to grnd 107 ohms<br /><br />Trigger<br />brn to w/blk 1238<br />wht to w/blk 1238<br />purple to w/blk 1237<br /><br />Do you think it is possible for the stator to have an intermittent problem? Or do you think another issue in the system could cause the bad stator readings? I am hoping tonight it will start and I can take these same readings again when it is starting and see what I get.<br /><br />Any thoughts or advise at this point?<br /><br />Thank You<br />Steve

 

[Laddies]

Re: 87 90 hp Mercury - No spark

Chances are it's the stator, but its hard to tell without a DVA to test it and it's a costly item, if you decide to by parts don't buy any of that crap from Mercury get Rapair/ CDI stuff--Bob

 

[harwich]

Re: 87 90 hp Mercury - No spark

Bob,<br /><br />I screwed up when I tested the stator earlier. I forgot to reset the range on my Ohm meter. I set it correctly and retested the blue wire and got 3690. I know both of those numbers are still a litle high. With that are you still inclined to think it is the stator?<br /><br />Thanks<br />Steve

 

[Laddies]

Re: 87 90 hp Mercury - No spark

Steve, I guess that with those readings it is probable OK, I never have had good luck with a OHM meter, but by those readings one would have to think switch box. The only things what will shut the whole system down are the kill circurt(blk/yellow wire) stator or switch box, if the trigger fails it only effects 1 or more cyl.--Bob

 

[harwich]

Re: 87 90 hp Mercury - No spark

Bob,<br /><br />Is there anyway to test the switch box for sure? If I took it off and took it to a marina is there anyway for them to test it? I hate to spend the money to replace it and still have the problem because it is a short somewhere. I know one day when I disconnected the blk/yellow wire it started as soon as I tried it again but I tried that last night with no luck.<br /><br />Thanks<br />Steve

 

[Laddies]

Re: 87 90 hp Mercury - No spark

There is not a test for a switch box, without a DVA and then it is a proccess of elaimnation, It would make me nervous to just throwing parts at. Try to get someone with a DVA to test it for you--Bob

 

[harwich]

Re: 87 90 hp Mercury - No spark

Yea, I talked to a marina about it. I think from what you have told me it is either a short somewhere or the switch box. With it being intermittent would using a DVA even be able to positively eliminate a short as the possible culprit? If it is a short and it is shorting out when they test the switchbox they would not get good voltage off of it right? Or am I missing something? I think the DVA would be able to eliminate the stator and trigger completely as a possible issue, but could it definately tell me if it is a short in the wiring or the switchbox?<br /><br />Thanks<br />Steve

 

[Nauteal]

Re: 87 90 hp Mercury - No spark

I need to get in on this topic. I believe I have the same engine you are describing and I am in the middle of a simular problem. 1987 3/Cyl 90 H.P Mercury.<br /><br />Mine is on a 24' pontoon boat. We were out cruising the other day. The boat was running just fine. We decided to stop and drift for a while. About an hour later when I went to restart the motor, it started-up, but as soon as I went to put it in gear it shut down and has not fired since. I took it to this marine mechanic I know and he said it need a stator and a power pack. It also just happens he favors Evinrudes and Johnsons. He sort of thumbed his nose up at Mercurys.<br /><br />Something in the back of my head tells me I need a second opnion and I can't find anyone to get me in for a month.<br /><br />Your feedback?

 

[harwich]

Re: 87 90 hp Mercury - No spark

My feedback would be to hope that Bob will respond to you. He is very knowledgable, where as I know very very little about boat engines.

 

[Laddies]

Re: 87 90 hp Mercury - No spark

Steve. with a DVA you can ck stator and trigger output and if they are correct then you can ck input and output at the switch box and you are testing the system under real load conditions, where when you OHM test there is no load so in some cases the system will test good because there is no load on it--Bob

 

[Laddies]

Re: 87 90 hp Mercury - No spark

Nauteal, although it is not impossible for the stator and switch box to go bad at the same time, I would wonder about a servicemans ability and honesty if without testing they wanted to throw the two most expencive parts in the system at the engine. In general I tell people to askm the mechanic to explain how the broken system functions and listen carefully to he awnser if it sounds reasonable he propably knows what he is doing, if he can't explain how it works he's a parts changer and if he blabs on and on he's a BSer

 

[harwich]

Re: 87 90 hp Mercury - No spark

OK- I understand. I don't know anyone that has a DVA, I already checked with the few people I thought might have one. I will probably just take it to the marina and pay them to diagnose it.<br /><br />Thanks for all of your help.

 

[Laddies]

Re: 87 90 hp Mercury - No spark

Ya some times it's best and cheapest to bit the bullet--Bob

 

[Nauteal]

Re: 87 90 hp Mercury - No spark

Laddies, Is it possible to test the Stator and Power Pack without pulling them off the engine?

 

[Laddies]

Re: 87 90 hp Mercury - No spark

Thats the way to ck them with a DVA on the engine for best results--Bob

 

[Nauteal]

Re: 87 90 hp Mercury - No spark

The reason I asked about how you check the Stator and the Power Pack is to get an idea if that mechanic truly really bothered to check those items. Or was he part swapping to cover his behind. I have had other mechanics say would relace them both if they needed to replace one of them.

 

[harwich]

Re: 87 90 hp Mercury - No spark

Nauteal,<br /><br /> I am far from being an expert but I don't see why they would replace both. I can see replacing the trigger when you replace the stator because they are both under the flywheel and there is a fair amount of labor involved in pulling the fly wheel to get to them but the switch is out in the open and can be replaced in about 10 minutes. These are also both $200 + parts. I will be interested to see what laddies says. Looking at his profile I believe he is a professional marine mechanic.

 

[Nauteal]

Re: 87 90 hp Mercury - No spark

Thanks Harwich, I knew those parts were not cheap. I just have not decided if I want to repair or buy something else . . . maybe even New. Bottom line that is what I am evaluating.

 

[Laddies]

Re: 87 90 hp Mercury - No spark

I am back, interesting these questions, this morning the first job of the day was a 60 hp 3 cyl. no spark it was running on the river and just quit dead cked it with a DVA it had a bad stator replaced it and it started right up and ran fine. As I was working on it I thought abought the OHM test so when I was done I tested it and it tested fine with the ohm test, thats why I always say to ck the voltage not the ohm's. As far as replacing the trigger because the flywheel is off I wouldn't inless the wires looked bad, triggers seldom go bad in our area and with the cost of a stator it ruins the day about enough--Bob