11855
New Member
On my engine the leads and the coil are not separate so I have to swap the complete CDM module.
2004 Mariner/Mercury 40hp 2-Stroke idling rough and won't rev up in gear
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11855
New Member
Folks, quick update. I got down to the boat this evening. I did a spark plug test using the top CDM module and there was no spark as expected. As before the engine was running on the bottom cylinder only. I then stopped the engine and removed both CDM modules and swapped them. I then started the engine and sure enough it was now running on just the top cylinder.
it does appear that the root cause was the top CDM module. I went ahead and ordered two new modules from Amazon. It may take a couple of weeks. My modules have 4pin connectors so I went with 2 of these.
Flymotor CDI CDM Module Coil for 114-7509 827509A10 A7 Mer-cury 100 115 135 150-250 hp : Amazon.co.uk: Automotive
I felt no point in replacing just one as knowing my luck the other would go soon.
thanks again for the great help and advice. I have certainty learn a lot.
will circle back once I get the new modules fitted
it does appear that the root cause was the top CDM module. I went ahead and ordered two new modules from Amazon. It may take a couple of weeks. My modules have 4pin connectors so I went with 2 of these.
Flymotor CDI CDM Module Coil for 114-7509 827509A10 A7 Mer-cury 100 115 135 150-250 hp : Amazon.co.uk: Automotive
I felt no point in replacing just one as knowing my luck the other would go soon.
thanks again for the great help and advice. I have certainty learn a lot.
will circle back once I get the new modules fitted
gordmac
Well-Known Member
Always good to find something wrong! Replacing both will give you a spare just in case.
11855
New Member
Hi folks, after 2 weeks the 2 new CDM Modules I ordered on Amazon arrived today so I made my way to the boat to try them out. I had already removed the two old units, one of which I believe was bad and the cause of my troubles.
After installing and connecting up the 2 modules I started the engine which fired up right away. I knew by the sound that all wasn't well. Sure enough I pulled the bottom plug lead and the engine kept running. I pulled that lead back then pulled the top plug and the engine stopped so it appears it was running on the top cylinder only. I was scratching my head going how can this be given I have 2 new modules. I then tried swapping the modules around and sure enough the problem moved from bottom cylinder to top cylinder i.e. it was now running on bottom cylinder.
I then decided to replace the top new CDM with the old one that was working previously. This time the engine wouldnt start and I was about to give up but thought I would go ahead and leave the engine with the 2 new CDM modules so I pulled out the old one and replaced it with the new one.
It was getting dark so I said I would start it up one more time and as soon as it started it sounded better. I did a quick plug leads test by pulling out the top and it kept running on the top. I replaced that lead and pulled out the bottom one and sure enough it stayed running on the bottom and it was ticking over really nicely as you can see here: 20210824_200509000_iOS.MOV
I didnt get a chance to take it out on the water and must admin I am a little anxious as I am not convinced the issue is truly resolved. On the way home I though perhaps the issue might be that the 4pin lead that connects to the CDM from the engine might not have made a good connection.
Anyway as of now the problem appears to be resolved after some trial and error.
Thanks,
Declan
After installing and connecting up the 2 modules I started the engine which fired up right away. I knew by the sound that all wasn't well. Sure enough I pulled the bottom plug lead and the engine kept running. I pulled that lead back then pulled the top plug and the engine stopped so it appears it was running on the top cylinder only. I was scratching my head going how can this be given I have 2 new modules. I then tried swapping the modules around and sure enough the problem moved from bottom cylinder to top cylinder i.e. it was now running on bottom cylinder.
I then decided to replace the top new CDM with the old one that was working previously. This time the engine wouldnt start and I was about to give up but thought I would go ahead and leave the engine with the 2 new CDM modules so I pulled out the old one and replaced it with the new one.
It was getting dark so I said I would start it up one more time and as soon as it started it sounded better. I did a quick plug leads test by pulling out the top and it kept running on the top. I replaced that lead and pulled out the bottom one and sure enough it stayed running on the bottom and it was ticking over really nicely as you can see here: 20210824_200509000_iOS.MOV
I didnt get a chance to take it out on the water and must admin I am a little anxious as I am not convinced the issue is truly resolved. On the way home I though perhaps the issue might be that the 4pin lead that connects to the CDM from the engine might not have made a good connection.
Anyway as of now the problem appears to be resolved after some trial and error.
Thanks,
Declan
gordmac
Well-Known Member
That is good news, the initial issue with the new ones may have been a poor connection. Do the connections look clean and do the plugs engage properly?
11855
New Member
From what I could tell the 4-pin connections did look OK and I did push to engage so the clip closed. The bottom connector is a bit harder to connect as it is in a awkward position.
Perhaps I should have wiped them with a cloth but maybe its best now to leave well alone. I will try to get the boat out for a test in the next couple of days.
Perhaps I should have wiped them with a cloth but maybe its best now to leave well alone. I will try to get the boat out for a test in the next couple of days.
gordmac
Well-Known Member
I tend to use contact cleaner on any contacts I dismantle.
11855
New Member
Thanks Gordmac, I have picked up a can of Contact cleaner.
11855
New Member
@Rappey @gordmac I got the boat out on the lake this evening it is running great.
Thanks so much for your help and advice. I bought the boat last year but only got it on the water this summer but not before I had to replace the steering cable and install a new starter motor and now the new CDM coil.
The joys of boat ownership I guess but worth it when you get to enjoy the waterways.
Ending this post. Hopefully it may help out another boat owner in future
Thanks so much for your help and advice. I bought the boat last year but only got it on the water this summer but not before I had to replace the steering cable and install a new starter motor and now the new CDM coil.
The joys of boat ownership I guess but worth it when you get to enjoy the waterways.
Ending this post. Hopefully it may help out another boat owner in future
11855
New Member
@BruceK @gordmac @Rappey
Folks, this should be my last request for help as the boating season ends here! I had some more drama since my last post.
After installing the 2 new CDM modules I though my problems were over however that wasn't to be. A week after my first test I was on the lake and gave the engine a good run. I opened it up to get the boat on the plane (approx 40kmh) which it did and it was running great. I was out for approx 40 mins when I entered a river to head to a mooring. I eased off the trottle to a speed of around 5-10km on the river and after about 5 mins I felt the power drop in pretty much exactly the same way when the first CDM failed. I tried increasing trottle but it wouldnt go beyond 1500rpm so I was fairly sure it was the same issue.
I limped backed to the marina on one cylinder and moored. I then pulled one plug lead and sure enough the engine was running on one cylinder - top. I then swapped the CDM modules and the problem moved so I figured one of the new CDM modules must have failed. After waiting 4-5 weeks to get it from Amazon I was pretty annoyed and wondered what to do next.
I checked amazon and noticed I could return the CDMs within 30 days. I then look at Marineparts.ie to check on the CDM there. To my surprise the CDMs were now less than half the price when I first checked a few weeks back. I decided to send back the 2 I got from amazon and order 2 new one from Marineparts (branded Recmar).
The 2 new Recmar CDM modules arrived after 3-4 days so I made my way to the boat to install them. Once installed I fired up the engine and I immediately knew it was running nicely on both cylinders but I did check to be 100% sure. This was unlike with the amazon CDM where I messed around a while before they worked. That might have been due to bad contacts as discussed above. I was really happy and decided to head out on the lake. The engine was running great as I motored around for about 30 mins not going over 2500rpm and I turned to head back to the marina. Another powerboat was passing by so I throttle down my boat down a little and as I did the engine just started to sound odd and it just cut out. I had never see it to do that before. I was then unable to start it and though I was in trouble. I then realized it had cut out in gear so once I switched to back to neutral I was able to get it to start. It started fine but once I gave it throttle in gear it died again.
I then checked the fuel line and primed the bulb a couple of times. I then try to restart it but it didnt start. I though it might be flooded so I gave it full throttle and it started. I let it idle for a few mins and gave it a few revs.
Then I put it in gear just enough to get me moving as I was in the middle of the lake and it was getting late. I didnt want to throttle up again incase it cut out so I whet very slowly back to the marina.
I made it back to the Marina and I flipped it to neutral. I knew it wasnt a CDM failure as it was ticking over fine. I double checked to ensure it was running on both cylinders and it was. I removed the plugs to check,
I have uploaded a video of the engine running and some photos showing the new CDMs installed and the plus to onedrive,
Boat video and pics of CDM and plugs
I haven't been back to boat since. I have a 55lb electric outboard that is just about able to move the boat as a backup so I will bring this with me next time.
As ever I would appreciate any tips or advice. I can only image for a running engine to cut out like that it must be either a fuel problem or no spark on the plugs.
Folks, this should be my last request for help as the boating season ends here! I had some more drama since my last post.
After installing the 2 new CDM modules I though my problems were over however that wasn't to be. A week after my first test I was on the lake and gave the engine a good run. I opened it up to get the boat on the plane (approx 40kmh) which it did and it was running great. I was out for approx 40 mins when I entered a river to head to a mooring. I eased off the trottle to a speed of around 5-10km on the river and after about 5 mins I felt the power drop in pretty much exactly the same way when the first CDM failed. I tried increasing trottle but it wouldnt go beyond 1500rpm so I was fairly sure it was the same issue.
I limped backed to the marina on one cylinder and moored. I then pulled one plug lead and sure enough the engine was running on one cylinder - top. I then swapped the CDM modules and the problem moved so I figured one of the new CDM modules must have failed. After waiting 4-5 weeks to get it from Amazon I was pretty annoyed and wondered what to do next.
I checked amazon and noticed I could return the CDMs within 30 days. I then look at Marineparts.ie to check on the CDM there. To my surprise the CDMs were now less than half the price when I first checked a few weeks back. I decided to send back the 2 I got from amazon and order 2 new one from Marineparts (branded Recmar).
The 2 new Recmar CDM modules arrived after 3-4 days so I made my way to the boat to install them. Once installed I fired up the engine and I immediately knew it was running nicely on both cylinders but I did check to be 100% sure. This was unlike with the amazon CDM where I messed around a while before they worked. That might have been due to bad contacts as discussed above. I was really happy and decided to head out on the lake. The engine was running great as I motored around for about 30 mins not going over 2500rpm and I turned to head back to the marina. Another powerboat was passing by so I throttle down my boat down a little and as I did the engine just started to sound odd and it just cut out. I had never see it to do that before. I was then unable to start it and though I was in trouble. I then realized it had cut out in gear so once I switched to back to neutral I was able to get it to start. It started fine but once I gave it throttle in gear it died again.
I then checked the fuel line and primed the bulb a couple of times. I then try to restart it but it didnt start. I though it might be flooded so I gave it full throttle and it started. I let it idle for a few mins and gave it a few revs.
Then I put it in gear just enough to get me moving as I was in the middle of the lake and it was getting late. I didnt want to throttle up again incase it cut out so I whet very slowly back to the marina.
I made it back to the Marina and I flipped it to neutral. I knew it wasnt a CDM failure as it was ticking over fine. I double checked to ensure it was running on both cylinders and it was. I removed the plugs to check,
I have uploaded a video of the engine running and some photos showing the new CDMs installed and the plus to onedrive,
Boat video and pics of CDM and plugs
I haven't been back to boat since. I have a 55lb electric outboard that is just about able to move the boat as a backup so I will bring this with me next time.
As ever I would appreciate any tips or advice. I can only image for a running engine to cut out like that it must be either a fuel problem or no spark on the plugs.
Last edited:
gordmac
Well-Known Member
That is a shame. If you have a good spark it may be a fuel problem, if it goes ok at low speed check the main jet. Also check that there is enough fuel flow. Is the tank connection drawing air?
BruceK
Well-Known Member
Sometimes one is so focused on the last problem one cannot see a new. To me it sounds very much like fuel starvation. The amount of times I forget to open the breather cap on the fuel tank in my tender and drive around oblivious for an hour or two before it cuts out in much the same circumstances as yours is something like 50-50. Yeah, I never learn. I'd go back to the lake with fresh eyes and a backup and go through the fuel checks. Fresh fuel with no water contaminants (dump old fuel), breather, fuel pump etc. Check for any air leakage, blocked filters etc etc and see if you can replicate the issue.
Rappey
Well-Known Member
The sound would be the telltale to what may be wrong.
11855
New Member
Thanks folks for the replies, @Rappey by sound odd I mean I got the distinct feeling it was going to cut out, like the revs were dropping even though I didn’t touch the throttle. The same happened when I first restarted and tried to throttle up instead of adding power it just started to die and cut out.
Before I got it moving I did check the fuel tank and would guess it was a quarter full. I had a 10ltr portable tank so I topped up the main tank. I don’t know if this helped really other than it was after this I started and it stayed running but I didn’t throttle up in case it cut out.
At the start of the season the engine had a service at a marine service centre and a fuel/water separating filter was fitted. I also replaced the fuel line, primer bulb and connector to the engine (I had to reuse the connector on the quicksilver tank).
I will get to the boat over the weekend and try it again and check the fuel line and connectors
Before I got it moving I did check the fuel tank and would guess it was a quarter full. I had a 10ltr portable tank so I topped up the main tank. I don’t know if this helped really other than it was after this I started and it stayed running but I didn’t throttle up in case it cut out.
At the start of the season the engine had a service at a marine service centre and a fuel/water separating filter was fitted. I also replaced the fuel line, primer bulb and connector to the engine (I had to reuse the connector on the quicksilver tank).
I will get to the boat over the weekend and try it again and check the fuel line and connectors