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Old 28 January 2020, 14:24   #1
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ECU for 20hp

Hi

Do u think if I swapped my 15hp Suzuki efi ECU for a 20hp .if I swapped back when serviced or issues as still in warrenty it would show up ?

Just wondering as relatively reasonable option to get ob to 20
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Old 28 January 2020, 14:48   #2
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Have you priced the ECU? I'm guessing £350-£400?

Too much cost and hassle in my mind for a modest improvement. If the 5hp less bothers you just buy a nearly new 20hp and sell yours.

Re the data retrieval at service time... I would guess the comprehensive data stored is all in the ECU so effectively plugging the "not used between services" ECU back in at service time would make it look as if the engine hadn't run at all for that period. If I was servicing it I'd suss what you were up to.
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Old 28 January 2020, 14:52   #3
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371 for the ECU . The new 20 is 2400 to 2900 depending on supplier.

My 2018 worth around 1500 to 1700 as a guess so a good bit cheaper with a new ECU rather than new ob.
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Old 28 January 2020, 14:54   #4
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Can't find a nearly new 20 but as u say not much more power , going to check next week as couple of guys meeting up with a 20
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Old 28 January 2020, 16:17   #5
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Also it is rarely just a single item change as "folklore" will often suggest. You need to look at every aspect that affects performance such as inlet tract, injectors, throttle body, exhaust tube etc to see what differences are there.

For example on the DF15 you have a restrictor in the inlet manifold that will need taking out and replacing each time if you are bothered about servicing to meet the warranty.

And to be fair you can't compare costs of yours vs a new one. There have been several 2/3yr old Suzuki DF20 models sell for £1500-£1600 over recent years. So if you also reckon yours at that sort of figure then a direct swap costwise looks possible.
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Old 28 January 2020, 16:57   #6
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Have you priced the ECU? I'm guessing £350-£400?

Too much cost and hassle in my mind for a modest improvement. If the 5hp less bothers you just buy a nearly new 20hp and sell yours.

Re the data retrieval at service time... I would guess the comprehensive data stored is all in the ECU so effectively plugging the "not used between services" ECU back in at service time would make it look as if the engine hadn't run at all for that period. If I was servicing it I'd suss what you were up to.
Absolutely right the computer will pick it up and void warranty
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Old 28 January 2020, 19:15   #7
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If you want the extra hp & your sure thats all it needs to gain it then just forget the warranty. Do the servicing yourself and put some of the money you saved aside in case you have to repair something. Most engines people pay to service to keep up the warranty never actually claim under the warranty anyway
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Old 29 January 2020, 03:39   #8
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you have to ask yourself why you want to upgrade if its top speed you might get 2 knots more at WOT with the 20, if its performance and load carrying then consider a prop change come down a pitch cost around £60 ok you lose top end a bit but the engine will be more responsive especially in the chop & plane quicker.
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Old 29 January 2020, 05:58   #9
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I'd wondered what prop pitch Cumbria had on his Suzuki DF15. In 2016 when I bought my DF20 new they were being supplied with different pitch props at random. Mine was due to come with 12" which was way over-pitched.... I grumbled and they fitted an 11" but I still had to buy a 10" for best performance overall.

My experience with various 15hp motors is a 9" usually does the trick in average use, good starting point anyway.

RE the warranty it's a personal thing and much depend on having a decent local dealer a short drive away. But I went the way Beamishken advises with mine... worked out the cost to me was about £500 and 8hrs travelling over the warranty period more than if I did DIY servicing... and I could do a better job than our nearest dealer.
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Old 29 January 2020, 06:16   #10
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agree david re warranty i pursued that route with mine through the trouble i had and cost a bomb,
the reason i said prop change with my 25 i went 10,11,12 inch pitch 11 being a good allrounder if you want to wait for response, the 10 gives more crisp control at the sacrifice of top end which you need a lot less on most days. the research i did although not absolute you gain about 2 knots per 5hp with a sib & at £400 plus to change parts isnt worth it IMO, whereas £60 for a prop which can be swapped out when the load lightens is a bargain
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Old 29 January 2020, 09:24   #11
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i had to contact central marine services for some bits so i asked about the 15-20 upgrade for the ECU see below




Engine: Upgrade 15hp up to 20hp



Suzuki states No! there are other factors

Also it would if attempted eliminate any Warranty



Regards



Walter
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Old 29 January 2020, 12:22   #12
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Quote:
Originally Posted by jeffstevens763@g View Post
i had to contact central marine services for some bits so i asked about the 15-20 upgrade for the ECU see below




Engine: Upgrade 15hp up to 20hp



Suzuki states No! there are other factors

Also it would if attempted eliminate any Warranty



Regards



Walter
They would have to say that though wouldn't they
Or people would be buying 15s and an extra ecu instead of going to the expense of buying a 20. The ideal scenario would be if someone had a 20 to borrow an ecu from
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Old 29 January 2020, 13:16   #13
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Well since my conversation went I have a mate who wants to upgrade a 15 to a 20 but keep his warranty and keep the budget below part exchange new or secondhand I thought that was good enough of a reply. Also looking on the Ron hale site the difference between the two is £500 new which kind of blows your theory out the water
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Old 29 January 2020, 13:53   #14
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I've had more of a look into this as it interests me. As far as I can see the camshaft is the same for 15&20, similarly the injectors and throttle body. Apart from the ECU it seems there is just the inlet restrictor to swap out for the gauze & seal as in the pics below.

Your 15 should have the restrictor as on the left, part 9, and you need replace with parts 6 & 7 in the right diagram.

However if you did decide on the upgrade check with your dealer for the parts that relate to your year and serial number.

Furthermore if you have a 9" pitch prop also budget to upgrade that to a 10" to get the best from 20hp.
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Old 29 January 2020, 13:59   #15
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Wonder if take restrictor out without ECU what happens , if the ECU will adjust .. I did think the 10 had the restrictitor and 15 not .
Thx for all comments appreciated
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Old 29 January 2020, 14:14   #16
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My guess is the fuelling on the 20hp ECU will be altered for the extra airflow... possibility you might be running far too lean with just the restrictor out and existing ECU given this is already a lean burn engine. This could damage the engine.

BTW the 9.9 has an even smaller restrictor and yet again a different ECU... it may have a different camshaft too.
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Old 29 January 2020, 14:17   #17
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Kinda wondering about the lean burn ... Maybe a small alteration to the restrictitor may work . Drilling it out a little .
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Old 29 January 2020, 14:30   #18
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Thing is compared to car engines that often cruise on the motorway at an easy 2000rpm an outboard at speed is likely thrashing along at 5000rpm+. You may not know you are running too lean until your pistons look like this..
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Old 29 January 2020, 22:05   #19
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Quote:
Originally Posted by Fenlander View Post
My guess is the fuelling on the 20hp ECU will be altered for the extra airflow... possibility you might be running far too lean with just the restrictor out and existing ECU given this is already a lean burn engine. This could damage the engine.

BTW the 9.9 has an even smaller restrictor and yet again a different ECU... it may have a different camshaft too.
Fuelling and timing should be altered depending on the octane of the fuel and atmospheric pressure etc. The ecu learns and builds an internal map over time. I can't imagine there's no closed loop and oxygen sensor? Therefore should be ok removing the restrictor completely. The 20HP ecu probably allows a higher rpm to deliver the extra goodies.

Incidentally I met a yachtie at Salcombe who said he'd had his 15HP ecu reprogrammed. I do believe him and that it's possible.
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Old 30 January 2020, 04:15   #20
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The sensors on the Suzuki 15/20 Efi system... in addition to the usual throttle and cam/crank posn sensors... are engine temp, air temp, air pressure. (Sensors listed in fault code chart below)

So it looks like it's not closed loop and has no adaptive ability.

And that's why for a newish £2000+ outboard I'd not risk experimenting for a possible 1kt increase in top speed.

I'm picking 1kt out of the air for a part tuning upgrade as Suzuki give just a 2.5kt increase for a proper 20 over a 15 and that's on a 3.4m RIB which will have a hull that would probably allow the extra power to translate into a greater speed increase than a SIB.
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