25.5 - request engine advice

[jyjohnson]

Hi folks. Today I purchased a Hunter 25.5 which to my un-trained eye looks to be in decent shape (very dry everywhere I looked).

However on our maiden voyage the Mercury 5hp (2 cycle) died. I think it is over-heating and shutting off; we noticed there was no stream of water shooting from the back bottom of the engine. Does this usually indicate the impeller is broken?

What are your thoughts on repairing vs replacing with a used engine (maybe slightly more HP)? I'm in a lake (so there are no currents, etc.).

Also, should I be looking at "long shaft" engines only, or will "short-shaft" engines work?

Thanks!

 

[kloudie1]

Best to stay with a long shaft engine.. Could be a broken impeller or could be something plugging the water passages, especially if the engine has been out of the water for a while... The impeller is pretty easy but the other might require a minor tear-down to fix.. If you aren't comfortable with the work, a good shop could probably do the work for less than half of what a new engine would cost.. A 5 hp is probably fine on a lake for that boat..
Welcome to the forum !

 

[Benny17441]

Stick a piece of wire up the engine's "pee" hole to see if there is any obstruction. I agree with Kloudie that the 5HP should be fine for the lake and as far as it being a short shaft should be fine too as you will not see the deep ocean swells that require a long shaft. With the sale of small two stroke outboards being banned in the US and other countries you have an engine that is grandfathered and it might be desirable to get it fixed. The two stroke engines are much lighter than the 4 strokes that are replacing them. Besides having a high power to weight ratio they are simpler to work on and their light weight facilitates getting it on and off the motor mount. On the downside they do require mixing the gasoline with the oil and the cost of operation is a little higher but they do provide better performance in acceleration.

 

[sailorladyliz]

Congrats on your purchase. The Hunter 25.5 is a fun boat. If you choose to purchase a new motor you might measure the height of the motor mount to the water before you decide on a short shaft or long shaft.

 

[Regular Guy]

I second on a damaged water pump impeller. You can buy a kit with all you need, the impeller and gaskets, etc. It is not really difficult to exchange, the lower shaft has to be removed. The manual how to do that is surely to find on the internet. Don't forget to put the little drive key!!
Without the proper water flow the engine overheats and will shut off.

 

[twodzusfittings]

Everything everyone has pointed out is true. One more thing is check the vent holes on the 2 stroke piston. As the engine burns oil/fuel mix, it builds crap on the vent exhaust holes of the piston. This usually happens faster if the oil to fuel ratio is incorrect. As to "a little more expensive to run" i get four times more out of my six gallon tank with my 9.8 Nissan long shaft than my old Evinrude Yachtwin 9.9. At $2.00 a gallon, that's huge. Based on the current gas costs, i have two more seasons, before it's paid for itself.

 

[jyjohnson]

Thanks all! I spent all Saturday replacing the impeller. The original one was completely destroyed and I think melted all over the housing, etc. I tried to clean it out. Now water is coming out! Yay!

However, I'm not sure if the F/N/R gearing is working correctly. It wants to stay in F but if I wiggle the selector a little I think it will stay in N (I haven't taken it out on the water yet). I'm not sure if this issue was there previously or if I messed something up when I put the lower unit back on (which was the only time I cursed during the whole procedure).

 

[Justin_NSA]

You probably moved the linkage rod. It should be easy to adjust.
The 25.5 is a heavy boat, but stick with the 5HP until you know for sure you want something bigger. E.g. my Mac26S was much lighter but I felt more confident in a blow after I went from a 5HP to a 9.9. ($1,300 later)

 

[Crazy Dave Condon]

with a two stroke the oil mixture to gas is 25 parts of gas to 1 of oil or ratio of 25 to 1. the mercury was built by Tohatsu if memory serves me correct as a former dealer. Do clean and check the gap of the spark plug but if worn, replace.

 

[twodzusfittings]

CDC is incorrect. 50:1 is the ratio.
See: https://www.reference.com/vehicles/oil-gas-mix-should-use-mercury-outboard-motor-76f9eaa78aa2c729

 

[Crazy Dave Condon]

sorry about that and Twodzusfittings you are so correct. 25:1 is for break in period but we are dealing with a used not new engine. Thank you for advising. Old fartitis is setting in my posterior end.