Short shaft Long shaft not know how

[Mihali]

Howdy all,<br />I believe I did an oops.<br />I recently obtained and Ebtide 1978 16 foot Bass boat, with nothing on it for good price. 99.00<br /><br />So, I began throwing parts on it I had around, and got to the point of needing a motor, I was running it with a 5 horse Honda 4 stroke long shaft spare I had.<br /><br />Honda pushed the 16 foot boat about 4 or 5 miles an hour.<br /><br />Well,<br />I decided boat was a keeper, and wanted a faster motor.<br />I didn't notice that the transom was 20 inches.<br />The motor I bought Johnson 1961 40 horse rds 23<br />and is a short shaft 15 inches. <br />Until I took it out for a test run and fishing.<br />And<br />with a friends gps it pushed 8.5 miles an hour.<br />Seemed a little slow.<br /><br />Needless to say I just wanted another opinion.<br />If you were to look at the pictures at:<br /><br /><br /> Shareaproject.com <br /> http://www.shareaproject.com/pages/projectThumbs,p,163,00.html <br /><br />Symptom:<br />Upon acceleration it seems to grab then slip probably due to propeller ventilation. When I accelerate more bow goes up and of course propeller goes deeper and the grab and slip stops. But I cannot get any speed. <br /><br /><br />Question:<br />1.in your alls opinion should the Johnson 40 horse push this boat faster if extension was added?<br /><br />2.Do you think this motor is under powered for the boat. If I would like to go maybe 20. <br />(Boat is rated for 85 Horse and is pretty solid)<br /><br />2.Do you think investment in extension would do the trick for more speed?<br /><br />4.Any body had a short shaft then changed to long shaft with same horse power or motor and tell me the difference.<br /><br />Thanks <br />Mitchell

 

[lark2004]

Re: Short shaft Long shaft not know how

You definitly need to get the longshaft parts.<br /><br />The motor should be able to get you to 20 mph. I wouldn't be surprised if you have spark problems on one or posibly both cylinders.<br />Do a spark test, the spark on these motors should be able to jump at least 1/4" - 1/2" gap with a nice blue arc, if it's orange, then you will need to pull the flywheel and check the coils and points.

 

[gatorred]

Re: Short shaft Long shaft not know how

if it was mine I get a 75 hp motor and stainless steal prop and a set back or jackplate, your live well pickup will cause blow out with alum prop if not set very low

 

[bay rat]

Re: Short shaft Long shaft not know how

maybe a dolphin would work. its about twenty dollars and it bolts on like a fin above the prop.good luck it seems like a cheap option

 

[bay rat]

Re: Short shaft Long shaft not know how

disregaurd i looked at your pictures and you have one alreadt.maybe cheap stable trim tabs.

 

[Silvertip]

Re: Short shaft Long shaft not know how

40 HP is simply not enough oomph for that boat to achieve any measure of performance. Put two people in it along with some gear and you'll be lucky to get it on-plane. A newer 75 HP minimum would be a better choice rather than spending money on other parts and then wondering if it will help.

 

[tashasdaddy]

Re: Short shaft Long shaft not know how

use to have a boat like this. it is much heavier than it looks. you need a long shaft with trim & tilt, and atleast 75HP. I would fix all the holes in the transom before i do anything. what good is a power unit, if you don't have anything the hang it on