timing belt replacement 75hp johnson

fredskid · Jun 4, 2007

Now that I have my new used timing belt, (thanks for your help finding it on ebay). Is there anything special to getting it on? I've got it on the distributer, and the nut off the flywheel. However the flywheel doesn't want to come off. My question while simple in nature is this, gear puller and brute force or is there some thing else i need to do. I just don't want to wreck some thing by accident. Youse guys have been great with all your help so far, thanks....,mike
p.s. this is for a 1965 75hp johnson

F_R · Jun 5, 2007

Re: timing belt replacement 75hp johnson

To make life easier, it should go on the flywheel before the distributor. I suppose it could go on the distributor first, but it would make timing it a pain.

Use a 3-bolt type puller screwed into the 3 holes near the center. NEVER use a puller that grips the outer rim of the flywheel!! You need a decent puller that won't break, and high strength grade-8 bolts. Attach puller and as you say use brute force. It will suddenly pop off when you pull hard enough.

When you put it back on, the tapers must be clean and dry and use a torque wrench to tighten the nut to 70-85 ft/lbs. This is very important!!!

fredskid · Jun 5, 2007

Re: timing belt replacement 75hp johnson

Thank you sir, I'll have to go out and get me one of those. Ya can never have enough tools, or is it ya never have what ya need, oh well. Quick question about the timing. I line up the arrows on the flywheel and put on the belt, but do i need a timing light or will it be pretty close aLready? I've never messed with a outboard, this boat had a mercruiser till the block cracked this winter, thanks again....,mike

F_R · Jun 5, 2007

Re: timing belt replacement 75hp johnson

The timing marks are all you need, both on the flywheel and distributor.

Chris1956 · Jun 5, 2007

Re: timing belt replacement 75hp johnson

Fred, It that motor is anyrhing like my '59 50HP, you need to synch the ignition timing with the carb, as well. There should be a timing mark on the distributor bracket. Line up the flywheel with the timing marks on the block, set the throttle to match the dist. pulley base with the dist. bracket. Turn the dist. pulley to match the dist bracket and pulley base and install the timing belt. Now without moving the throttle, make sure the cam on the carb is just touching the roller that opens the butterfly.

fredskid · Jun 5, 2007

Re: timing belt replacement 75hp johnson

oK thanks alot, I'll let ya know how it goes...,mike

fredskid · Jun 7, 2007

Re: timing belt replacement 75hp johnson

OK got my puller attached with my #8 bolts, I have it reefed down to where the threaded shaft is bending, question is the 3, 5/16 bolts are the only thing holding the flywheel down correct? I'm kinda surprized it hasen't gave by now. I tapped the outside with a wooden dowel, and tapped the top of the puller with my hammer ( made me feel better), but no dice. Have at it? or is there something I missed.....,mike.

PS ended up with a steering wheel puller, fits perfect. works?we'll see.

Chris1956 · Jun 7, 2007

Re: timing belt replacement 75hp johnson

Fred, You have confused me with the three 5/6" bolts remark. Isn't the flywheel held on by a large single nut in the center? Other than that friction between the tapered crankshaft and the flywheel holds it.

fredskid · Jun 7, 2007

Re: timing belt replacement 75hp johnson

I stand corrected, the three bolts hold the manuel start cover on. I had to use them to pull the flywheel, which did come off, with a clang. I have my marks lined up and belt on, i just gotta see about the throttle stuff youse guys are talking about, plus cleaning out the mouse sstuff out of the lowerunit. thanks for all your help so far...,mike

CATransplant · Jun 7, 2007

Re: timing belt replacement 75hp johnson

Be sure to torque that flywheel nut (the big one) down to the proper spec. I don't have that torque specification for your engine handy. If you don't either, ask.

If you don't torque it properly the crankshaft key will shear off.

James R · Jun 7, 2007

Re: timing belt replacement 75hp johnson

Hi.
I have to say that the syncronization, ie throttle to timing, can be a little tricky. My suggestion is to buy the manual for the motor. You can pick one up used on Ebay for small bucks. Follow the directions very carefully and you should be ok. I have just worked on a similar motor and I have another in my shop. I always invest in the manuals for any motor I work on.

Evinrude Boater · Jun 7, 2007

Re: timing belt replacement 75hp johnson

I replaced my timing belt on my '64 Evinrude 75HP and I don't remember pulling the flywheel. Isn't the belt large enough to slip over? Well, I guess you've got it off now anyways.

F_R · Jun 7, 2007

Re: timing belt replacement 75hp johnson

Evinrude Boater said:
I replaced my timing belt on my '64 Evinrude 75HP and I don't remember pulling the flywheel. Isn't the belt large enough to slip over? Well, I guess you've got it off now anyways.

I questioned that too, but then thought maybe he has the big Unicharger alternator??? I dunno. Model number do help sometimes.

timing belt replacement 75hp johnson

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