Entropy Posted June 20, 2007 Report Share Posted June 20, 2007 (edited) I have a 1991 25 hp Mariner outboard with elect. start on my boat. At 3/5 throttle to full throttle it bogs down, if you leave it in “bog down mode” after a couple of minutes it opens up and comes out of the hole and attains full throttle. It starts fine, idles fine, runs at 1/5th to 3/5 throttle fine, but it’s when you hit the throttle to bring it up on plane that it bogs down.... ??? The marine mechanic I have been taking it to has tried to fix it 5 times, each time it is like the first day I took it in there. I’m going on 5 weeks without a boat. So, far he has cleaned the carb. twice, checked to see that the electric choke is working ok, then narrowed it down to an ignition problem. When it is “acting up” (and only on the water) there is an inconsistent spark to one cylinder. When he switched the leads to the coils the “inconsistent spark” switched to the other cylinder. He replaced the CDI module and that did nothing, then replaced the “trigger”, and that did nothing. He now says he is going to take a good look at it and try and fix it .... ??? Does anyone have any ideas on what could be going wrong? (Other than I might want to take it to another mechanic). Entropy Edited June 20, 2007 by Entropy Link to comment Share on other sites More sharing options...
Cast-Away Posted June 20, 2007 Report Share Posted June 20, 2007 A very simple check is the gap on the plugs. This can cause the exact problem that you are having. Also try changing the plugs. The older Mercs use to have reed valves between the carb and the block. If they got gummed up, they had to be replaced, which was quite an expensive job to have done. If all else fails, take it to Paul at Topgun Marine just north of Bradford. He is awesome! 905-775-0862 Link to comment Share on other sites More sharing options...
yellowboat Posted June 20, 2007 Report Share Posted June 20, 2007 I have the exact same problem with my 70 merc. Link to comment Share on other sites More sharing options...
taper Posted June 20, 2007 Report Share Posted June 20, 2007 Do you have separate coils or are they in the CDI. If they are seperate it could be the coil or the lead itself. Link to comment Share on other sites More sharing options...
Wes Bender Posted June 20, 2007 Report Share Posted June 20, 2007 First off, I wouldn't pay for the next repair. Sounds like he is just throwing parts at it instead of a proper diagnosis/repair. In turn costing you more and more money. Do you know this guy? Or is this the first time using this mechanic. Something just sounds fishy there. Personnaly, I would just take it to another mechanic if you have that option. Link to comment Share on other sites More sharing options...
Entropy Posted June 20, 2007 Author Report Share Posted June 20, 2007 I have only paid $102 so far, he (the mechanic) says there is no way to test for the cause of this probem other than repace the parts. Right now it is him who now owns the parts tried, not me, so that's good. The coils are separate. My Father has had this guy do the head gasket on this motor, and other work as well, everyone seems to recomend him. Entropy Link to comment Share on other sites More sharing options...
DanD Posted June 20, 2007 Report Share Posted June 20, 2007 With what you’re saying that the misfire follows a coil when the leads were switched; I would be replacing that ignition coil. It may have an internal short that when under load the secondary voltage (spark) is to low in KV and cannot bridge the spark plug gap. I’m an automotive tech and we’ve been seeing this kind of problem more and more with the multiple coil ignition systems that most manufacturers have switched to. Dan. Link to comment Share on other sites More sharing options...
ecmilley Posted June 21, 2007 Report Share Posted June 21, 2007 sounds like a coil problem to me as well. Link to comment Share on other sites More sharing options...
gussser Posted June 21, 2007 Report Share Posted June 21, 2007 Good answer DAN--- Common sense still has a place in hi tech repairs. Under load coil can not function properly. Link to comment Share on other sites More sharing options...
Dutch Posted June 21, 2007 Report Share Posted June 21, 2007 Another good resource for you would be to post your question on iboats in the proper repair forum. Not that people around here don't know what they are talking about, but there's a huge number of MM's that frequesnt that site that specialize in certain brands of motors. It has helped me out a lot and gives varying perspectives. Link to comment Share on other sites More sharing options...
Bernie Posted June 21, 2007 Report Share Posted June 21, 2007 Dont think its a coil problem fellas. Entrophy said when the leads to the coils were switched the problem went to the other coil. Problem must be upstream of the coils. Link to comment Share on other sites More sharing options...
DanD Posted June 21, 2007 Report Share Posted June 21, 2007 No he didn't say the misfire went to the other coil he said. When he switched the leads to the coils the “inconsistent spark” switched to the other cylinder. I feel for Entropy’s mechanic; there’s nothing worse then trying to repair something that’s kind of broke. If whatever is causing this would out and out break/burn out a couple of meter checks and he’d find the problem. Dan. Link to comment Share on other sites More sharing options...
misfish Posted June 21, 2007 Report Share Posted June 21, 2007 (edited) Yep I,ll second topgun. Paul is a great MM. You can try here aswell. http://www.outboardrepairs.com/ Edited June 21, 2007 by misfish Link to comment Share on other sites More sharing options...
Big Cliff Posted June 21, 2007 Report Share Posted June 21, 2007 I have a 1991 25 hp Mariner outboard with elect. start on my boat. At 3/5 throttle to full throttle it bogs down, if you leave it in “bog down mode” after a couple of minutes it opens up and comes out of the hole and attains full throttle. It starts fine, idles fine, runs at 1/5th to 3/5 throttle fine, but it’s when you hit the throttle to bring it up on plane that it bogs down.... ??? Entropy I might be way off base here but would a shorted coil correct itself after a couple of minutes of being under load? Is there a chance that there is some kind of "limiter control" in this CDI module or that part of the circuit? I know they have them in some weedeaters etc. Link to comment Share on other sites More sharing options...
hawg_hauler Posted June 21, 2007 Report Share Posted June 21, 2007 Sorry guys but if you read the wording correctly, Nipissing is right on the money. However, with that said I am not convinced it is an ignition failure. It may just be what the tech is telling you whats wrong, because he really doesn't know himself. Reeds on that block are very simple to check. Without witnessing what is happening, I think most would have a problem trying to properly diagnose your problem. Link to comment Share on other sites More sharing options...
Terry Posted June 21, 2007 Report Share Posted June 21, 2007 ok if he switches the leads to the coils..would he not have to switch the plug wires too so the spark timing is right and if he did that, would you not expect the other cylinder to have the problem if it was the coil??????? or am I missing something Link to comment Share on other sites More sharing options...
Entropy Posted June 21, 2007 Author Report Share Posted June 21, 2007 What Nipissing is saying is what the mechanic has said "Dont think its a coil problem fellas. Entrophy said when the leads to the coils were switched the problem went to the other coil {The the other cylinder} . Problem must be upstream of the coils. He has tried repacing the CDI Module (aka, power pack, ignition mod.), and the trigger. He still does not know what it is. I'm supposed to pick it up Tomorrow, Hope the darn thing runs right THIS TIME. Entropy Link to comment Share on other sites More sharing options...
Entropy Posted June 21, 2007 Author Report Share Posted June 21, 2007 Just got off the phone with the mechanic, says he has repalaced a coil at not cost. AND says it works for sure. I'll pick it up tomorrow and let you know Monday. Maybe the fist diagnosis was not right? Entropy Link to comment Share on other sites More sharing options...
tizfun Posted June 21, 2007 Report Share Posted June 21, 2007 Had the same problem with my 35 hp Johnson.. Trolled fine, started up perfect, hit the throttle to get her going, after a couple of seconds, she would bog.. Mechanic found it to be a loose wire on my starter.. I didn't believe it but it was it.. Tightened it up and it was gone.. Tiz Link to comment Share on other sites More sharing options...
misfish Posted June 21, 2007 Report Share Posted June 21, 2007 Anyone seen what a coil looks like when it,s done????????????????????????? Looks like an old clacker beat,n together to long.LOL Remember the clackers??????????????? LOL Hope thats the cure E. Link to comment Share on other sites More sharing options...
Fisherman Posted June 22, 2007 Report Share Posted June 22, 2007 Anyone seen what a coil looks like when it,s done????????????????????????? Looks like an old clacker beat,n together to long.LOL Remember the clackers??????????????? LOL Hope thats the cure E. CLACKER BALLS...them things on a string that would just hurt a bit if you got some body parts in the way? Link to comment Share on other sites More sharing options...
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