Can I use existing tach? Was for an I/O

[LoneGunman]

I purchased a project boat last week. It originally had an I/O in it but came with a 1995 2 stroke 4 cylinder Mercury 115 in it. Are I/O tachs the same as OB tachs?

It's not hooked up now a long with 99% of the rest of the electrical system.

I'm totally clueless when it comes to OB's, looking on Ebay for a manual now.

 

[sleepinin]

Re: Can I use existing tach? Was for an I/O

I believe they are not the same. The back of the tach you have will have a selector switch for the number of cylinders. You need one that has a pulse selector switch. You then go to the table that comes with the tach and figure how to set it for your motor.

 

[ricksrster]

Re: Can I use existing tach? Was for an I/O

Some tachs you can. If the selector switch is marked with both "C" for cylinder and "P" for pulse. You want 6P.

 

[Chris1956]

Re: Can I use existing tach? Was for an I/O

Lonegunman, To convert an I/O hull to carry an outboard requires a lot of effort and expense. Why did the prevoius owner go through all that and not change the Tach?

 

[LoneGunman]

Re: Can I use existing tach? Was for an I/O

Lonegunman, To convert an I/O hull to carry an outboard requires a lot of effort and expense. Why did the prevoius owner go through all that and not change the Tach?

Chris, I have no idea, he did a lot of screwed up things on this boat. The wiring is so bad I'm just going to rewire everything. A friend of mine is a boat captain and he restores boats, he checked it out last week and said I still got a great deal.

The guy I bought it from was using a portable fuel tank BELOW deck so the tank was venting below deck.

 

[Chris1956]

Re: Can I use existing tach? Was for an I/O

OK, I guess that begs the question. "Did he do a good job plugging the I/O hole in the transom, and beefing up the transom to hold that OB?" And of course "what kind of a boat has a "below decks", but is powered by a single 115HP OB? The boat sounds too large for that power.

 

[sleepinin]

Re: Can I use existing tach? Was for an I/O

Sounds pretty neat to me. I've never know anyone to have their transom come off. Are there a lot of sharks where you boat? d Get the service manual and it'll tell you how to wire everything. Also put in two batterys with a selector switch and a seperate electrical junction plate to hook all your accressories up to neatly. Also on your fuel tank think about the range you'll need. That engine probably burns 7 or 8 gallons an hour at cruising speed. You'll want to get at least a 40 gallon tank. I have an 80 on mine with a 150hp and I don't really ever have to worry about fuel. If your doing a lot of inland boating a smaller tank may be alright but I'd go as big as you can fit and can handle weight wise.