possible repower
- Thread starter Jim Wasko
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An old topic
Jim, you might want to cross post this to the CHerebuni forum also. Anyway we had this discusion severl weeks ago. Here is a link to one of my replies. http://archive.sailboatowners.com/archive/archiverview.tpl?rid=2005339145156.11&forumabr=cd&fno=18&&_psamp=psamp&&model=none&forum=none&andor=ws&keyword=m3-20&pr=p,r&ssite=HOW&srt=pdate&start=1&max=1&db=2005&cart=113700654632962 If you search the Forum with "m3-20" you can find the complete thread. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
Jim, you might want to cross post this to the CHerebuni forum also. Anyway we had this discusion severl weeks ago. Here is a link to one of my replies. http://archive.sailboatowners.com/archive/archiverview.tpl?rid=2005339145156.11&forumabr=cd&fno=18&&_psamp=psamp&&model=none&forum=none&andor=ws&keyword=m3-20&pr=p,r&ssite=HOW&srt=pdate&start=1&max=1&db=2005&cart=113700654632962 If you search the Forum with "m3-20" you can find the complete thread. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
No wories
I think I can post this long thread url http%3A//216.39.145.91/archive/archresults.tpl%3Fssite%3DHOW%26fno%3D0%26start%3D1%26requiredfields%3Dkeyword%252Cyear%26cart%3D11370290074539%26keyword%3DAdding%2Bto%2Bthe%2Bassumptions....%26model%3Dnone%26forum%3Dnone%26pr%3Dp%252Cr%26_ptitle%3Dptitle%252Brtitle%26_psamp%3Dpsamp%26andor%3Dws%26year%3D2005%26srt%3Dpdate Sorry to screw up the viewing of the page. Cut and paste everything between the URL brackets at the begining and end. Pat
I think I can post this long thread url http%3A//216.39.145.91/archive/archresults.tpl%3Fssite%3DHOW%26fno%3D0%26start%3D1%26requiredfields%3Dkeyword%252Cyear%26cart%3D11370290074539%26keyword%3DAdding%2Bto%2Bthe%2Bassumptions....%26model%3Dnone%26forum%3Dnone%26pr%3Dp%252Cr%26_ptitle%3Dptitle%252Brtitle%26_psamp%3Dpsamp%26andor%3Dws%26year%3D2005%26srt%3Dpdate Sorry to screw up the viewing of the page. Cut and paste everything between the URL brackets at the begining and end. Pat
B
Benny
waste of money
I would suspect your boat has a 1GM which is rated at 6.5HP. The 27 can easily attain a speed of 5.5 knots with the 1-GM. There has been fo a while and currently the only 1 cyl available is a 1GM10 which is rated at 8HP. The 2GM20 rated at 18HP is considerably more expensive, heavier, uses more fuel which may require a larger fuel tank and will not add much speed or power to the rig. It will require modifications to your motor mounts, shaft and prop. GM-1s were mated to the KM2A transmission while 2GM20s and 1GM10s were mated to the KM2C or KM2P transmission. If you have a known, used 2GM then go for it, but if you are looking to purchase new, your best option would be to repower with a 1-GM10 together with is mated transmission. The 2GM20 has a stronger alternator and the F model will have a closed cooling system which may be desired features for heavy sailing. Would the conversion to a 2GM increase the value of a 25 year old boat the answer is most likely not, would it increase the performance of the boat, only slightly unless you have to fight strong currents day in and day out. The cost and modifications necessary would be unwarranted under most normal conditions and performance expectations.
I would suspect your boat has a 1GM which is rated at 6.5HP. The 27 can easily attain a speed of 5.5 knots with the 1-GM. There has been fo a while and currently the only 1 cyl available is a 1GM10 which is rated at 8HP. The 2GM20 rated at 18HP is considerably more expensive, heavier, uses more fuel which may require a larger fuel tank and will not add much speed or power to the rig. It will require modifications to your motor mounts, shaft and prop. GM-1s were mated to the KM2A transmission while 2GM20s and 1GM10s were mated to the KM2C or KM2P transmission. If you have a known, used 2GM then go for it, but if you are looking to purchase new, your best option would be to repower with a 1-GM10 together with is mated transmission. The 2GM20 has a stronger alternator and the F model will have a closed cooling system which may be desired features for heavy sailing. Would the conversion to a 2GM increase the value of a 25 year old boat the answer is most likely not, would it increase the performance of the boat, only slightly unless you have to fight strong currents day in and day out. The cost and modifications necessary would be unwarranted under most normal conditions and performance expectations.
a waste?
not so sure about that Benny. The current motor I have is rated at 8hp according to the tag on the backside of the motor. and since I've had the boat for few years now, it has never motored quicker than 5 knots in pond water. If even the tide is against me, I can't do more than 4 at best and forget it if the wind is on the nose at the same time. I currently have the chance to purchase a 2gm that needs a rebuild for $200 plus the rebuild price. After reading other threads, I'm guessing it is possible to put a bigger motor in the boat, but, have to replace the transmission and prop. Not so bad actually.
not so sure about that Benny. The current motor I have is rated at 8hp according to the tag on the backside of the motor. and since I've had the boat for few years now, it has never motored quicker than 5 knots in pond water. If even the tide is against me, I can't do more than 4 at best and forget it if the wind is on the nose at the same time. I currently have the chance to purchase a 2gm that needs a rebuild for $200 plus the rebuild price. After reading other threads, I'm guessing it is possible to put a bigger motor in the boat, but, have to replace the transmission and prop. Not so bad actually.
Jim,
A few questions please, The 2GM is it just the motor? alternator? starter? What exact model of 2GM is it? there should be some suffix letters. What trans is on your 1GM? it'll be hard to read but should be cast into the backside. As far as fitment. The mounts should sit exactly in the same width. A 2gm is about 6" longer than a 1GM. SO you'll need to drill new holes to ballance the change in length. You might be able to use the rear mount holes, but watch the clearance at the front. I'm not realy concerned about the fuel consumption change. The shaft and coupler will bolt up, but you'll need to reprop. COntrol cables wil be the same, fuel line will be the same. The exhaust is larger, 2" on the 2GM. I'd take the opportunity to replace the system with new hose anyway. Rebuilding is fairly easy if you have experience. Parts costs are reasonable. I'd guess you'll have about 3000-3500 in the complete project. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
A few questions please, The 2GM is it just the motor? alternator? starter? What exact model of 2GM is it? there should be some suffix letters. What trans is on your 1GM? it'll be hard to read but should be cast into the backside. As far as fitment. The mounts should sit exactly in the same width. A 2gm is about 6" longer than a 1GM. SO you'll need to drill new holes to ballance the change in length. You might be able to use the rear mount holes, but watch the clearance at the front. I'm not realy concerned about the fuel consumption change. The shaft and coupler will bolt up, but you'll need to reprop. COntrol cables wil be the same, fuel line will be the same. The exhaust is larger, 2" on the 2GM. I'd take the opportunity to replace the system with new hose anyway. Rebuilding is fairly easy if you have experience. Parts costs are reasonable. I'd guess you'll have about 3000-3500 in the complete project. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
not sure
not sure Pat, I was on the phone with the owner and all I heard was 200 for 2gm something, rebuild and I basically get the whole kitten kaboodle.. But I am waiting for his call back so that I can line-up a good time to bring my truck over and grab it, so after that call, I can tell you specifically whats there and what isn't. I also just want to say that this isn't something I would normally do, but I want to take the boat from Connecticut down to Florida and back this summer via the ICW and I by all means need to be able to fight the current, power off a possible grounding and etc. Something I probably wont be able to do with anything under 8hp
not sure Pat, I was on the phone with the owner and all I heard was 200 for 2gm something, rebuild and I basically get the whole kitten kaboodle.. But I am waiting for his call back so that I can line-up a good time to bring my truck over and grab it, so after that call, I can tell you specifically whats there and what isn't. I also just want to say that this isn't something I would normally do, but I want to take the boat from Connecticut down to Florida and back this summer via the ICW and I by all means need to be able to fight the current, power off a possible grounding and etc. Something I probably wont be able to do with anything under 8hp
B
Benny
Not powering over 4knots.
Jim, if you cannot power over 4 knots with your 1-GM check that you can attain 3,400 RPM. If you cannot get the motor to RPM's even in neutral clean the bottom of the boat, replace air and fuel filter and clean the fuel/water separator and check the prop for condition and correct size and pitch. If you have done all this still cannot get the motor to RPMs under load your motor may be weak. Run a compression test to confirm its condition. If you are coming to Florida down "the Ditch" you should not have any problems with 1GM. Only once in 10+ years did we encounter a current the little chugger could not push through. (Doing 1 knot overland was not an option) The conversion is doable but consider the modifications, cost and work involved.
Jim, if you cannot power over 4 knots with your 1-GM check that you can attain 3,400 RPM. If you cannot get the motor to RPM's even in neutral clean the bottom of the boat, replace air and fuel filter and clean the fuel/water separator and check the prop for condition and correct size and pitch. If you have done all this still cannot get the motor to RPMs under load your motor may be weak. Run a compression test to confirm its condition. If you are coming to Florida down "the Ditch" you should not have any problems with 1GM. Only once in 10+ years did we encounter a current the little chugger could not push through. (Doing 1 knot overland was not an option) The conversion is doable but consider the modifications, cost and work involved.
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