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Perkins M20 alternator bracket

dougal boy

Junior Member
I just picked up an older Perkins M20, 1989, Trying to check it out before install. Does anyone know if I should look for an after market alternator bracket. I've been reading stories of the universal M25. I'd like to avoid those unfortunate problems. I haven't found any info on whether the M 20 has similar issues. Any thoughts? Thanks
 

Kevin A Wright

Member III
I put a Perkins M20 (new) into my E27 back in about 1995 or so. Great little engine and never had a lick of trouble with anything on it for the next 20 years when I sold it and moved up to an E35. If the 95 engine is the same as the design on the 89 ( and I don't see why they wouldn't be, the alternator bracket is a good simple design and will be just fine.

The problem was with the old Universal design which was stupid from the get go.

Kevin Wright
E35 Hydro Therapy
 

dougal boy

Junior Member
M 20

Thanks Kevin,
one more thing to cross off the list. Are there any other tidbits you can share, that I probably haven't thought of about this engine. I will be putting it in my E29. will she fit without too much trouble?? How about the shaft lining up? I know it was a long time ago, but any recollection would be most appreciated. I'm thinking alternator, starter, regulator, maybe electric fuel pump, to start. I don't want to have to crawl around after I install!!

Thanks again
Rich
 

Kevin A Wright

Member III
What engine do you have in there now? I had a 1977 E27 with the original A4 so there were some changes needed. The A4 had a 3/4" prop shaft with the diesel I increased that to 1", which meant new shaft, stuffing box, and prop. Had to put a larger cutlass bearing in but only the bearing itself, the strut took a 1" bearing just fine.

For the engine bed I had to add some Ash risers, about 2 1/4" thick I think, maybe 2 1/2" and about 4" wide. Bolted and 5200 those to the existing bed to get the engine high enough to align the shaft. That meant I had to raise the wood engine compartment cover about 1" to clear the new engine (added soundproofing at the same time).

As I remember the engine controls worked backwards from the A4 so had to redo all those. Got to keep the original Aluminum fuel tank though, just rinsed it out and added a fuel return line to it.

Of course had do some doctoring on the exhaust to get it to run right. Also added a red dot cabin heater to the cooling system while I was at it.

A few years after I also figured out I needed to change the raw water through hull to a larger size. The original was pretty tiny ID. While it cooled the engine OK, the increased velocity through the small opening kept sucking up kelp and clogging my strainer. Sometimes in the fall around here it got pretty bad.

Other than that, piece of cake ; ) I did all the work myself so by the time I was done knew everything inside and out. But it was worth it for 20 years of care free operation. As I said, a great little engine.

Here's a pic to see if it is the same one you have. You can see the risers I added to the bed.

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Kevin Wright
E35 Hydro Therapy
 

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dougal boy

Junior Member
M 20

Hey Kevin,
thanks for the info and pics. It didn't have an engine when I got it 2 years ago. I have been using a 15 hp honda outboard waiting for the right diesel to come along. The po told me it had a diesel in it before me, but had no info on it. The exhaust and controls are all on the same side as the M 20, so that is good. I'm not sure about the shaft size. Your E27 compartment original stringers are slightly higher than mine I think. I wont know till I get back to the boat. But it is good to see that it fits nicely in there. I to will be doing all my own work. Did you use the boom to lift it in place?, I did that on another boat and worked fine.
Its all fun!
Thanks
Rich
 

Kevin A Wright

Member III
If it had a diesel before you might luck out and save a lot of work (and $). If you have a diesel return line going to the fuel tank and shaft and prop are sized right that will be nice. I'd be sure to really clean out the fuel tank well before you start. If it has had some diesel sitting in there for a long time with no use it could really grow some interesting stuff in there.

Yes I used the boom and a come along to lift the engine in and out. Worked really slick, especially since I had to do it about 5 times to get everything aligned and installed properly.

Good luck!

Kevin Wright
E35 Hydro Therapy
 

dougal boy

Junior Member
prop size

Hey Kevin,
Engine is in and will be hooked up this week if all goes well.
Question; Do you remember your prop size? I'm getting too many different opinions.:confused:

Thanks
 

Kevin A Wright

Member III
Sorry I don't exactly remember. Gave all the records to the new owner as well. It was a big move up from the small 3 blade that was on the A4. I went to a 2 blade with the Perkins, either 11" or 12". I remember there was a little less than 1" clearance from the tip of the blade to the hull and it angled into the notch where the hull meets the rudder. That's less clearance than the guru's say, but I never had an issue with it with the heavier 1" shaft.

But man that thing could push. My new E35 with a bit more powerful motor and a 15" 3 blade fixed on it seems way underpowered to me now, even though I make an extra knot with the longer waterline. Takes me a lot longer to respond and get up to speed.

Kevin Wright
E35 Hydro Therapy
 

dougal boy

Junior Member
prop size

2 blade over a 3?
I would not have thought that, that is how confused I am. Ive been thinking 3 blade 12 RH ??. Pitch has got me.... 8 to 14:confused: I did not change the 3/4 shaft. I may be sorry. The PO ran a diesel with it. I guess I will know soon enough.

Thanks
 

JPS27

Member III
Rich,
not sure if this helps, but I repowered from an a4 to an old yanmar because it was what I could afford. I have an e27, 3/4" shaft. I worked with michigan props and a trusted local prop shop. Like Kevin I went with something that doesn't have the full 15% clearance as recommended. My prop is an 11x14. And I couldn't be happier, so far. I'm confident with the changes in that engine pushes the boat as it should, and maxes out as it should. for a long time I kept the indigo blade on while I figured out what to do next and saved my pennies. on that old prop I had to "cruise" at a 2.5 knots so as not to rev the engine too high.

Anyone want an indigo prop at a good price? :rolleyes:

Jay
 

Kevin A Wright

Member III
Jay, an 11 x 14 2 blade sounds like what I had on the old Wright Off.

Rich, I went with the 2 blade because that is what the local prop shop suggested based on the design of boat, engine, etc. I was young back then and didn't know much about it so went with their suggestion and was happy with it for 20 years.

Really the difference between a 2 and 3 blade fixed prop on a sail boat comes down to how much sailing and how much motoring you do. A 3 blade had more drag under sail, but more 'bite' under motor. I've been told a 3 blade will back better with less prop walk and I can kind of see that on my new boat, although Ericsons typically back like pigs (but turn like ballerinas ;).

For the same boat/motor application a 3 blade will usually be smaller in diameter and 1" of pitch lower than the 2 blade for the same boat.

If you have a local prop shop, stop in and ask them. They will want the details of the boat and engine, and can look up on their charts the best prop for you.

Good luck

Kevin Wright
E35 Hydro Therapy
 

JPS27

Member III
^^what Kevin says. But I went with the 3 blade. I was traumatized by my reverse, coupled with prevailing winds, narrow fairway, my lack of skill, etc that seemed to mostly work against my boat and with it's serious prop walk. I considered changing my boat's name to "wiffle ball". I had a "therapy session" with the prop shop owner and concluded that my relatively novice sailing self would be happier with more control under power than a .25 to .5 kt. So far I couldn't be happier and since I don't race I don't notice a lack of speed under sail. btw, we worked out the dimensions of the prop with michigan wheel and my prop guy. I think it was a bit much, but I'm happy. I can actual reverse pretty confidently, and have entertained people driving up the creek backwards for reversing practice (is there a pun in there?)
 

Kevin A Wright

Member III
I switched to a 3 blade on the E35 for those reasons as well. On the old boat I just learned you couldn't back out of a slip to stbd (or even straight if there was a wind), but turn to port was fine. Always tried to get a bow in port side tieup.

The plus of all that prop walk was you could 'parallel park' an e27 using it. Just stick your nose into the spot you want and use the walk to suck your stern right up to the dock. You can also make her turn perfect pirouettes (to stbd only) with no forward motion by rocking between forward and reverse. Was asked many times if I had bow thrusters on that boat. That way I didn't have to back down long fairways as long as there was a boat length plus 6" of room, you just spun 180 and motored out ( or preferably you spun 180 before you tied up to the finger pier so you were pointed out for the departure.

Kevin Wright
E35 Hydro Therapy
 

dougal boy

Junior Member
prop talk

Thanks Kevin, Jay for your insight. I think 3 blade is for me, for all the reasons mentioned. After securing the engine, aligning the shaft, looks like 1-1/2 clearance with a 12" prop. There is 12x13, 1" shaft on CL currently. Any info on shaft spacers, not my preference, but price is right. :rolleyes:...
Thanks
Rich
 
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