Shaft length for 26D

[MrBill_FLL]

FWIW, on 2 strokes the only difference between 9.9 and 15 is(was) the carb size.

weight is same, but it will use more fuel.

 

[tkanzler]

It's getting fuel. It is overheating, then cutting off. He did replace the impeller on the pump and it is getting good water exiting the motor.

It's possible there are bits of old impeller in the passages. A marine mechanic would know this, of course, and if the old impeller had come apart, he would have had an 'a-ha' moment. But that doesn't mean there aren't old bits in there from some time in the past. A good pee stream doesn't mean all the passages are clear.

Edit: Oh, and here's another vote for a 25" shaft. Having had sailboats with off-center engines, I've found through hard experience that the more the conditions require engine power, the more likely the prop is to try not to stay wet.

 

[walt]

Been there with the bits of impeller clogging up the plumbing..

I put on a extra long shaft Nissan 9.8 on my 26S but moved it up 2.5 inches and back 2 inches so that it would fully rotate. The resulting 2.5 inches deeper than the standard long shaft makes a noticable difference in the prop not comming out of the water. This has worked great for three seasons now.

 

[MacNCheese]

moved it up 2.5 inches. The resulting 2.5 inches deeper than the standard long shaft makes a noticable difference in the prop not comming out of the water.

I'm not following. If You moved up (as in out of the water) by 2 inches, how does that make 2 inches deeper in the water?

 

[Bob McL]

The resulting 2.5 inches deeper than the standard long shaft

 

[anchorclanker]

I think he means he put a longer shaft motor on the boat, but raised it a couple inches. So its still deeper, but only by half the distance.

I need to correct something. While some manufacturers use a different carb to get more rated power, a 9.8 and 15 HP Johnson for example, the 15 wont really use any appreciable more fuel providing power, until output exceeds 9.8 HP. As long as its throttled back the two motors should be about equal.

As long as the cylinders look good, if the mechanic can clean the passageways and get it cooling it should still be a good motor. Even though the impeller was replaced, it may be a good idea to check, or just replace the rubbers on both ends of the water tube. The powerhead may need to come off, but its not terribly difficult and worth the added labor to get everything correct. Remember that those small motors use the same impeller as the short shafts. The added height makes it that much more difficult for water to making to the top with adequate flow. That motor should have a pee tube coming off the top of the engine routed to the starboard quarter. Make sure its clear and peeing well.

My concern is why is stopping. If its stopping due to seizing, it may be past its life. You'll know soon as he pulls the head.

 

[dawg2]

I think he means he put a longer shaft motor on the boat, but raised it a couple inches. So its still deeper, but only by half the distance.

I need to correct something. While some manufacturers use a different carb to get more rated power, a 9.8 and 15 HP Johnson for example, the 15 wont really use any appreciable more fuel providing power, until output exceeds 9.8 HP. As long as its throttled back the two motors should be about equal.

As long as the cylinders look good, if the mechanic can clean the passageways and get it cooling it should still be a good motor. Even though the impeller was replaced, it may be a good idea to check, or just replace the rubbers on both ends of the water tube. The powerhead may need to come off, but its not terribly difficult and worth the added labor to get everything correct. Remember that those small motors use the same impeller as the short shafts. The added height makes it that much more difficult for water to making to the top with adequate flow. That motor should have a pee tube coming off the top of the engine routed to the starboard quarter. Make sure its clear and peeing well.

My concern is why is stopping. If its stopping due to seizing, it may be past its life. You'll know soon as he pulls the head.

They pulled the head and said it had an exhaust leak. It also had a seized t-stat as well. They have ordered a new exhaust seal and will put on a new head gasket too. HOPEFULLY that will stop the overheating and cutting off issue. I would like a new motor, but would rather get a couple years out of this one first.

 

[walt]

Correct. That motor (newer 9.8 Nissan or Tohatsuu 4stk) wont fully rotate on the 26 classic transom. This is important to some, not so important to others but I like it to rotate.

Long shaft is 20 inches, Extra long shaft is 25 inches which would be 5 inches deeper on the stock transom but I raised the transom by 2.5 inches to get the rotation. So with the Xlong shaft, Im still 2.5 inch deeper than the long shaft which solved the main problem I had of the prop caviting when I was motor sailing (happens on one tack only).

I had some initial issues with the idle jet being clogged up (probably some tiny object left over from manufacturing) so I replaced the jets and the motor has run great since then.

 

[Doc_holiday]

In regard to depth and turning. Would one of those brackets that hinge downward be an option? Mine mounts on the transom and is a long shaft but it's not very deep in the water and has slight turning limitations. But I digress, would one of those brackets help?

My problem is no tiller for the motor, PO must have removed when he installed the remote throttle/shifter. I can turn it by hand but if the motor were back and down another 6 or 8 inches, I would have to stretch to get to it