1GM10 repower to Beta 14

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dnewl...@msn.com

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Apr 18, 2025, 2:49:59 PMApr 18
to J/92 Owners
There's been a post or 2 about this and I recently did it.  Some random comments and if any questions, LMK.

I did this myself over a few weeks, still holding down a job and marriage, with the exception of a friend to help remove/install the engines into the doghouse. 

The engine is slightly bigger and I had 22" of vertical clearance already cut into the front of the doghouse from a previous 1GM10 repower.  I didn't need to cut any more.  

The Beta manual dimensions are ALMOST spot on as I cut a 1/4" ply template of the engine length, width, trans flange and position of engine mounts (that require new holes).  I tried very hard to exact my trans flange placement from the 1GM10 and all looked great until I tightened everything up.  Motor ended up 3/8" more forward than I measured for/wanted, that cascaded into driveline shaft fitment issues.  Quickest move was to mill the face of the prop hub .30 to get me more shaft as I had no more on the front end to play with.  

Existing shift/throttle cables worked, with 2 exceptions.  I had to flip the linkage behind the throttle arm to get forward = forward.  And, the trans cable shift coupler was frozen to the cable threads and broke = new cable needed.  

Positive/Negative existing wiring reached to the new Beta locations with some simple re-routing. 

Exhaust is on the port side of the Beta, but they sell a tall cross-over manifold and it kind of gets to the starboard side. It doesn't reach as far to starboard as the 1GM10 so you need a bendy hose and/or a slight movement of the water muffler inboard off the starboard engine bulkhead.  I'm still fine-tuning this and I bet I'll end up with a few inches of the muffler sticking out the back of the engine box to get good hose alignment, and a few inches inboard of the starboard bulkhead. 

Engines mounts required a 3/8" shim.  I probably could have gone 1/2".  Beta does have various mount options and I should have inquired more about this (or they should have played better offense).  Maybe they have a mount that matches the 1GM10 bolt pattern?  I know they use this motor as a drop-in for the Atomic.

Fuel lines go to 8 mm or 5/16" 

Water line goes from 1/2" to 3/4". 

Heat exchanger gets pretty close to the port engine access panel.  I'm going to clearance mine.  

Some engine noise insullation has been removed (back side of forward access panel and port side panel for instance, and sides low around the mounts).

Transmission flange bolt pattern is different, so you'll need a different shaft coupler (and drive saver if one is used).  A machinist could cut your existing coupler but it needs 4 new holes plus a larger pilot bushing dimension.  I stayed with my 3/4" drive shaft.

I went with the 2:1 gear box (from 2.62:1) and my 13x9R prop was calculating good per Flex O Fold's and Beta's calculators, but water tested way off.  I could only get 3000 RPM's and 3600 is needed for proper running and warranty.  12X8R prop is perfect.  There is also a 2.5:1 Beta gearbox available but I don't know if I would see better effeciency with more prop diameter. 

I got the larger control panel and it required some slight shaving of the top/bottom edge and rounding the corners so it would fit.  Nothing major.  I also added 4 more mounting screw so a total of 8 are holding it in place rather than 1 in each corner.

1 thing I did that was very helpful was build a platform at the mouth of the doghouse, at the same level as the lowest level of the opening.  3/4" ply.  This not only was a great place to plop the motors before picking with the halyard, I spent quite a bit of time laying on it doing install/cleaning/drilling/epoxying/bleeding/cussing.  I also found it somewhat easy to step out of the cabin with it, so I could stow the ladder the entire time I worked on this project.

1 thing should have done (and will do) is enlarge the port side engine access panel.  I'm going to 21" by 29".  This will help get better access to the +/- wiring terminals on the engine and also some help with the mounts.  

The motor runs really well and I think it's about 14 lbs heavier than the 1GM10.  Transmission is a cone clutch type and smooth.  Serviceablility is fantastic with oil/fuel filters and impellor all front and center of the engine.  Built-in oil pump out.  I also have better access to all aspects of the engine mounts for some reason (maybe wire rerouting freed up space and insulation carve-out).  

Beta was very good to work with.  The motor was in stock and they ran it before it went in the crate.  Their online store for parts is very well organized with a 10% discount.  It won't make up for the chunk I threw down for this thing, but it will help slightly.  They were good with quick email responses and such.

I'm off to the Newport to Ensenada race next weekend and that return will be it's first gig.  We'll see how she does.  




Colin

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Apr 19, 2025, 7:40:19 AMApr 19
to J/92 Owners
Wow!  Thanks for the detailed account.  It sounds like a big undertaking but glad it all worked out. 

Good luck in the Newport to Ensenada!

Cheers,
Colin Mann
J/92 Poohsticks #8

Andy S

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Dec 3, 2025, 4:56:39 PMDec 3
to J/92 Owners
Hey David

Is the performance difference significant from the yanmar to the Kubota?  Are you pushing faster in flat water and chop?  I have my 1GM out of the boat now and at a crossroads with the Beta quote in my inbox waiting for me.  thanks!

Andy
#61 Switch

Peter Norman

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Dec 5, 2025, 6:39:17 AMDec 5
to J/92 Owners
You will not regret having the extra power. My last boat had a 1GM and i had a scare in 35 knots wind against tide, could only make 1 knot if lucky. I put a 2YM in and at 15hp made a huge difference.
My 92s has a VP D13 and has plenty of power and makes 5 knots in 30 knots which is OK. The question is whether or not you can justify the outlay and effort.

dnewl...@msn.com

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Dec 5, 2025, 10:19:13 AMDec 5
to J/92 Owners
Hi Andy,

Under normal conditions, I'm really not using the extra HP.  But it's there if needed.  I run mine very similar to how I ran the 1GM10 with regards to hull speed.  Maybe a touch faster, but nothing significant.  Fuel consumption a little better, but hardly worth mentioning.  Transom 100% clear of soot.  The reliability, ability to do maintenance, and just the overall confidence I have in it is worth what I paid.  And, I did the exhaust hose and muffler as well.  If I ever sell the boat, I recoup some of the cost. 

For me, it was an absolute no-brainer.  

Where are you?  If you pull the trigger and want more information on the engine template I made or the platform, let me know and I'll post some pics.  

Andy S

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Dec 5, 2025, 11:56:32 AMDec 5
to J/92 Owners
I already have my 1GM out of the boat.  I either need to rebuild or go new.  For the past 2 season, I have had lots of unburned fuel (soot) coming out of the exhaust.  Thinking it was a fuel issue,  I have changed the high pressure pump and the injector.  No change.  The end of this season, I noticed oily residue in the air intake and exhaust leaking around the injector.  I'm thinking a top end rebuild at the minimum.  I have owned the boat for 15 years and have pushed the engine hard the entire time.  we use the boat to race and cruise and both of those things require a 15 mile trip to get there at a minimum.  So, I push the engine hard to maximize speed.  If I gain just one knot of speed, that's an hour for some of my trips.  A smoother, quieter 2 cylinder has been on my mind for a few years.  Thank you for the info.  i would appreciate any info in addition to what you have already provided.  I'm in western NY on Lake Ontario.  please contact me directly at andy...@gmail.com.  thanks!!!

Andy

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