I have a Mac19 that came with a Honda BF40. I wanted a cost effective way to add more power without sacrificing reliability. After much research, I came up with two modifications that satsified my needs to bring it up to the full 50hp+, being a camshaft swap and an ignition modification.
You guys with the Honda BF50 already have the "hot" camshaft, but the ignition modification that I did on my BF40 could add 1-2mph more top end to you boats. The only downside to this is just slightly more NOx emissions and a more "racey" character in the midrange.
Feel free to PM me if interested.....
Chris Hinkel
Honda BF50 ignition modification for MO power.
Chris, is this something you could post on the Mac Mods page?
It might get more visibility there long term. Plus, I think we need to get some more M19 mods up there.
I'd personally love to see a write up on the rest of your mods (motor bracket, centerboard line, etc.) there as well...
Good to see you on this board.
Kevin (from the M19 Yahoo Group)
It might get more visibility there long term. Plus, I think we need to get some more M19 mods up there.
I'd personally love to see a write up on the rest of your mods (motor bracket, centerboard line, etc.) there as well... Good to see you on this board.
Kevin (from the M19 Yahoo Group)
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cbhinkel
- Deckhand
- Posts: 42
- Joined: Thu Jan 15, 2004 3:40 pm
- Location: Mac19 w/ Honda BF50; Escondido, CA
Hey Kevin,
I was hoping that some of the Mac19 group would check this forum out. You can get some good ideas from the 26' boat modifications to be applied to our boats. Good to see you here as well.
I would consider posting some of my modifications on this site, but I don't think enough Mac19 people visit this to make it worth my while. Sheesh, they don't even have a "Mac19" emoticons for us to use! ;>) I noticed that you made your own Mac19 figure and it looks good. At some point, I will more thoroughly document my boat for you and other Mac19-ers
But seriously, the Honda outboard ignition modification is something I want to keep under wraps as it might be the basis of a Honda outboard tuning business I might dabble in. Also, it's somewhat complicated to perform unless you're mechanically inclined. I believe I could get up to 10 more ponies from a BF50 and up to 15 from a BF40. I also want to try to "soup up" the BF75 and BF90 engines too. This is one of several ideas I have up my sleaves.
-Chris
I was hoping that some of the Mac19 group would check this forum out. You can get some good ideas from the 26' boat modifications to be applied to our boats. Good to see you here as well.
I would consider posting some of my modifications on this site, but I don't think enough Mac19 people visit this to make it worth my while. Sheesh, they don't even have a "Mac19" emoticons for us to use! ;>) I noticed that you made your own Mac19 figure and it looks good. At some point, I will more thoroughly document my boat for you and other Mac19-ers
But seriously, the Honda outboard ignition modification is something I want to keep under wraps as it might be the basis of a Honda outboard tuning business I might dabble in. Also, it's somewhat complicated to perform unless you're mechanically inclined. I believe I could get up to 10 more ponies from a BF50 and up to 15 from a BF40. I also want to try to "soup up" the BF75 and BF90 engines too. This is one of several ideas I have up my sleaves.
-Chris
I'd sure like to see some of the other M19's here too. The Yahoo group is great for specifics, but this site is just so much easier to track, search, etc. I'm going to get things started on the Mods board as soon as I wrap up my steering project. The rest of my boat is stock, or very common mods.
But you're right. At the very least, we need an Emoticon if we ever want to rule the world. I'll drop Heath a PM with a request to add this one to the list.
Regarding the motor mods. If it weren't for the distance from here to CA, I'd be the first in line for your HP upgrade. But you'd have to convert my motor from tiller to remote in order to solve my current dilemma first.
But you're right. At the very least, we need an Emoticon if we ever want to rule the world. I'll drop Heath a PM with a request to add this one to the list.
Regarding the motor mods. If it weren't for the distance from here to CA, I'd be the first in line for your HP upgrade. But you'd have to convert my motor from tiller to remote in order to solve my current dilemma first.
Not quite. You need to scan your owners manual and send it to Heath so he can post it on the Manuals Page 
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Don T
- Admiral
- Posts: 1084
- Joined: Fri Jan 02, 2004 7:13 pm
- Sailboat: MacGregor 26X
- Location: 95 2600 "SS OTTER" - Portland OR - Tohatsu 50 - Hull#64 (May 95)
Hello:
About the timing curve / camshaft mod. If your intent is to increase the total timing or mod the curve itself, better make sure that there is no detonation even with low grade marine gas that may have been sitting around a while. Detonation under full throttle can be hard to hear. If the curve is not just right you may burn a hole in a piston. Believe me it does not take long. Slightly lean mixture and/or just a hare too much timing will produce good power right up until it quits.
Do you have a way to verify combustion / exhaust temperature? Do those engines have knock sensors or maybe you could fit one so you can verify?
About the timing curve / camshaft mod. If your intent is to increase the total timing or mod the curve itself, better make sure that there is no detonation even with low grade marine gas that may have been sitting around a while. Detonation under full throttle can be hard to hear. If the curve is not just right you may burn a hole in a piston. Believe me it does not take long. Slightly lean mixture and/or just a hare too much timing will produce good power right up until it quits.
Do you have a way to verify combustion / exhaust temperature? Do those engines have knock sensors or maybe you could fit one so you can verify?
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cbhinkel
- Deckhand
- Posts: 42
- Joined: Thu Jan 15, 2004 3:40 pm
- Location: Mac19 w/ Honda BF50; Escondido, CA
I've raced automobiles and modified engines most of my life. Detonation was a primary concern and the inability to start the outboard due to compression lock was a secondary consideration when performing this modification.
The BF40 is rated for 4 to 28 degrees BTDC and the BF50 is rated for 4 to 32 degrees total ignition advance. These values are very mild total ignition advances for a gasoline engine, which typical hit 40 degrees BTDC at the 9.2:1 compression ratio and the 86 octane the engines are rated for. So why doesn't Honda set the ignition advance higher? It's because they need to have these engines rated for 3star emissions, which is a significant challenge when not using catalytic converters. It also provides for a very smooth running motor as well. Cranking down the ignition advance gets the purring emission friendly outboard motor that Honda wants. Unfortunately, it also kills the power, especially at high rpm where there is less time for the ignition event to take place.
Currently, I have 8 degrees of ignition advance dialed into my old BF40 (36 degrees total BTDC now) and with with using crappy 87 octance gasoline, I haven't heard a hint of detonation. Believe me, I've been listening for it! For a BF50 modification, I would suggest no more the 5 degrees ignition advance unless you want to dedicated yourself to use 91 octane gasoline, then your could get away with the full 8 degrees that I have. With just 6 degrees of ignition advance before I put in the BF50 camshaft, I went from 13.5mph to 16mph in speed trials using two way averages and a GPS. This is with my 2000lb+ overweight Mac19. I'm now pushing 20mphs with my current set-up.
The modification consists of modifying the stock ignition trigger, and it can be set anywhere from stock to full advance. I wish I could change the timing curve, but that's hardcoded into the engine ignition control unit, and can't be changed(by me at least). Also, these engines don't have a knock sensor, so you have to be careful to obtain gasoline at a reputable station. Lastly, exhaust temperatures can actually go down with additional ignition advance as more of the combustion takes place inside the cylinder transferring the available energy to mechanical power vs. being spent on heat.
I'm pretty sure the BF40/50 outboard platform could be capable of approaching a reliable 60hp using 91 octane gasoline with following mix:
-BF50 head with its 1.0mm larger intake valves
-BF50 camshaft for better breathing, reground camshaft for lighter boats.
-BF40 carbs as they are calibrated richer (and would reduce the likelihood of detonation)
-Chris Hinkel's ignition trigger with up to 8 degrees total advance or more?
I hope that answers some of your questions and concerns.
-Chris
(woo-hoo!)
The BF40 is rated for 4 to 28 degrees BTDC and the BF50 is rated for 4 to 32 degrees total ignition advance. These values are very mild total ignition advances for a gasoline engine, which typical hit 40 degrees BTDC at the 9.2:1 compression ratio and the 86 octane the engines are rated for. So why doesn't Honda set the ignition advance higher? It's because they need to have these engines rated for 3star emissions, which is a significant challenge when not using catalytic converters. It also provides for a very smooth running motor as well. Cranking down the ignition advance gets the purring emission friendly outboard motor that Honda wants. Unfortunately, it also kills the power, especially at high rpm where there is less time for the ignition event to take place.
Currently, I have 8 degrees of ignition advance dialed into my old BF40 (36 degrees total BTDC now) and with with using crappy 87 octance gasoline, I haven't heard a hint of detonation. Believe me, I've been listening for it! For a BF50 modification, I would suggest no more the 5 degrees ignition advance unless you want to dedicated yourself to use 91 octane gasoline, then your could get away with the full 8 degrees that I have. With just 6 degrees of ignition advance before I put in the BF50 camshaft, I went from 13.5mph to 16mph in speed trials using two way averages and a GPS. This is with my 2000lb+ overweight Mac19. I'm now pushing 20mphs with my current set-up.
The modification consists of modifying the stock ignition trigger, and it can be set anywhere from stock to full advance. I wish I could change the timing curve, but that's hardcoded into the engine ignition control unit, and can't be changed(by me at least). Also, these engines don't have a knock sensor, so you have to be careful to obtain gasoline at a reputable station. Lastly, exhaust temperatures can actually go down with additional ignition advance as more of the combustion takes place inside the cylinder transferring the available energy to mechanical power vs. being spent on heat.
I'm pretty sure the BF40/50 outboard platform could be capable of approaching a reliable 60hp using 91 octane gasoline with following mix:
-BF50 head with its 1.0mm larger intake valves
-BF50 camshaft for better breathing, reground camshaft for lighter boats.
-BF40 carbs as they are calibrated richer (and would reduce the likelihood of detonation)
-Chris Hinkel's ignition trigger with up to 8 degrees total advance or more?
I hope that answers some of your questions and concerns.
-Chris
(woo-hoo!)
I have used this ignition upgrade with great results
I used DirectHits in my 1995 Isuzu Trooper 3.2L gasoline engine to improve engine power and smoothness while towing my Mac26X. The Trooper was quicker to respond to the throttle and a slight mpg improvment around town. The DirectHits upgrade works best at high rpm and high load -- exactly what an outboard motor needs.
..
Results towing fully loaded Mac26X both ways a 300 mile frequent round trip.
Before = 9.0 mpg and the engine was struggling
After = 11.2 mpg and the engine was much smoother with power to spare
..
I did not put them in my outboard because the Suzuki DF50 has an ignition coil over each spark plug already.
..
I have asked several times before on this discussion for someone to try DirectHits in their Tohatsu two stroke 50 hp. No one has reported back about having tried this. I think the DirectHits would be a big help on the Honda and the Suzuki 60 & 70 hp outboards. I am not selling anything, but I am curious about the performance boost on a Mac26X and I think it is a shame not to get better MPG and lower emissions as a byproduct of this performance upgrade. When I bought mine there was a money back satisfaction guarantee, so nothing to loose.
..
http://www.directhits.com/
http://www.directhits.com/howitworks.html
testimonials DirectHits on outboard motors:
http://www.directhits.com/jrogers.html
http://www.directhits.com/britton.html[/url]
..
Results towing fully loaded Mac26X both ways a 300 mile frequent round trip.
Before = 9.0 mpg and the engine was struggling
After = 11.2 mpg and the engine was much smoother with power to spare
..
I did not put them in my outboard because the Suzuki DF50 has an ignition coil over each spark plug already.
..
I have asked several times before on this discussion for someone to try DirectHits in their Tohatsu two stroke 50 hp. No one has reported back about having tried this. I think the DirectHits would be a big help on the Honda and the Suzuki 60 & 70 hp outboards. I am not selling anything, but I am curious about the performance boost on a Mac26X and I think it is a shame not to get better MPG and lower emissions as a byproduct of this performance upgrade. When I bought mine there was a money back satisfaction guarantee, so nothing to loose.
..
http://www.directhits.com/
http://www.directhits.com/howitworks.html
testimonials DirectHits on outboard motors:
http://www.directhits.com/jrogers.html
http://www.directhits.com/britton.html[/url]
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Chip Hindes
- Admiral
- Posts: 2166
- Joined: Mon Jan 05, 2004 6:13 am
- Location: West Sand Lake, NY '01X, "Nextboat" 50HP Tohatsu
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kmclemore
- Site Admin
- Posts: 6263
- Joined: Sun Feb 08, 2004 9:24 am
- Sailboat: MacGregor 26X
- Location: Ambler, PA -- MACX2018A898 w/ Suzuki DF60AV -- 78 BW Harpoon 4.6 -- 2018 Tahoe 550TF w/ 150 Merc
Hey, Moe... Lemme see if I can give these 'short boat' guys a hand in becoming legit...Moe wrote:Not quite. You need to scan your owners manual and send it to Heath so he can post it on the Manuals Page
The Mac 19 manual is already 'on-line' here.. does that count?
(Just kidding about the 'short' stuff, of course... we're very glad to have you guys here!!)
Short is good here in South Dakota. Our M19 is just barely small enough to fit into the $600 a year slips. My 26x friend pays almost $1500.kmclemore wrote: Hey, Moe... Lemme see if I can give these 'short boat' guys a hand in becoming legit...
Anyway, thanks for bringing up the manual link. That's a nice site that has a lot of good M19 info. I also have a PDF of the manual I'll send to Heath. Now, I'm anxious to hear what the next hurdle is on our quest for equality.
Thanks for the welcome. There really is a lot that information that can be applied to our boats from this board. For example, right now I'm researching how much faster my M19 will be once I get the hull painted blue....kmclemore wrote:(Just kidding about the 'short' stuff, of course... we're very glad to have you guys here!!)