Inboard on the 12-foot rowboat, wow ... more info please.

lncc63 · Post by **lncc63** » Sat Jul 21, 2007 3:19 am

Hi Morten. An associate of ours posted these pictures from your builders gallery:

and we'd be very interested to know more about it. What kind of motor is that? What is the drive arrangement? Morten to you have the modification drawings to do this?

I personally would like to know if I can do this with the 15-ft dingy.

Kayak Jack · Post by **Kayak Jack** » Sat Jul 21, 2007 12:14 pm

Louis,

I'm not Morten, but that recoil starter on there looks like what Briggs & Stratton has used for about 60 years. And, it's an air cooled, single cylinder, horizontal crankshaft engine, likely about 3-5 horsepower.

Boatplans.dk · Post by **Boatplans.dk** » Sun Jul 22, 2007 1:26 am

Here is what I know about the arrangement. It's a 2 hp lawnmower gasoline engine (Briggs & Stratton I can tell from the pictures). It's placed on a rubber engine mounting and uses a V-belt for reduction gear, 2.5:1. It uses very little gasoline and is only making a little noise.

I don't have any drawings for the inboard arrangement, the builder 'invented' everything himself. It can be a bit difficult to see all the details on the pictures in my gallery, so you can download the pictures in a better resolution from here:

http://www.boatplans.dk/logo/rowboat_inboard.zip (2.5 MB)

When an inboard engine can be installed in the 12-ft rowboat, I can't see why it should not be possible in the 15-ft dinghy also. You got all the principles from the pictures

Kayak Jack · Post by **Kayak Jack** » Sun Jul 22, 2007 9:08 am

What does he have in that small bottle on the transom? It looks like a lube oil of some kind, but I can't see where the tube leads to anything mechanical.

He's going to have the devil's own time trying to change the oil in heat engine the way it's mounted. The oil drain dribbles right out onto an engine mount, and he will have dirty oil all over the aft section of his boat. Unless, he removes the engine from the mount for that operation.

Boatplans.dk · Post by **Boatplans.dk** » Sun Jul 22, 2007 11:11 am

Not sure but it could be lubricant for the stern tube or some bearings. Normally you use grease for the stern tube, but who knows

This small engine would be easy to remove, change the oil and put back in.

Kayak Jack · Post by **Kayak Jack** » Sat Aug 04, 2007 1:59 pm

I've been thinking about this. If the user of this, or a similar engine, reads this, here is IMPORTANT information.

These engines were notorious for self destruction. The MOST important consideration on them is lubrication. Engine oil is of paramount importance. We cannot ignore these little ones like we can our car. They will not stand up to it.

The engines were often made economically, (read CHEAP). Crank shafts were not forged, they were cast. Engine main bearings were not ball or roller, in many cases they were not even bronze bushings. Briggs & Stratton, and later many other manufacturers too, simply bored the die-cast crankcases for bearings, and used the native aluminum itself as a bearing surface. They wore out quite fast.

Connecting rods were not forged either, again, die-cast aluminum. They had no babbitt bearings on the rod throw bearing surface at the crankshaft. Again, soft aluminum right on the cast iron. And, again, rapid wear.

Engine oil was recommended to be changed at 25 hours of use. You may be able to get away with that in a marine use where dust is not prevalent. However, oil is cheap and metal is expensive. I'd recommend changing at 15-20 hours of use.

Engine oil level is a real culprit here. Many users thought that if you removed the fill plug and could see oil, it was OK. Don't you bet on it. It MUST be full to a point of overflowing. THAT is the proper oil level. You FILL it to the point of overflowing, and MAINTAIN it to the point of overflowing. There is no margin of safety here. Users must fill to the point of overflowing, and check it again every 2-3 hours of use. Add even a half cup if you can.

After a season or two of use, these engines developed what I called a "balanced flow oil system" - they would use it almost as fast as you could pour it in.

If I've shocked you - good. Losing an engine to internal failure on a lawnmower is a frustrating inconvenience. Losing an engine at sea can be more important. DO NOT go to sea without a back up method of propulsion. Otherwise, carry a live aboard capability in your boat.