It's Me and the 45 again

[Jcrain]

If you have read the previos posts from me then you know that the 45 is hanging on the back of a previosly sunken boat. After about a year and a half, I got the thing back on the water and running....decent. I finaly talked my wife into going for a spin. Sort of a "See, I told you I could do it" type of ride. <br />I launched the boat at the public ramp and cruised across to our dock. It ran excellent. The wife got in and off we went. It coughed a time or two but picked right up and was doing great. The wife said to take her back, she didn't trust it. I dropped her off at the dock and went to cruise around. After about half an hour, the thing started running rough at WOT so I'd ease back on the throttle and it'd smooth out. Back to WOT and it'd do ok for a few min then miss a bit. I decided that my outboard mech skills may not be as good as I had thought so I headed to the loading ramp. As I slowed down to a bout 1500 rpms, she died and I haven't got her started since. Once home, I checked for spark, feul and have both. What should I check next?

 

[Jcrain]

Re: It's Me and the 45 again

Opps, The engine is a 1976 45 hp battery ingnition, model 457HF

 

[Jcrain]

Re: It's Me and the 45 again

Opps, The engine is a 1976 45 hp battery ingnition, model 457HF

 

[fixin]

Re: It's Me and the 45 again

I'd replace the fuel pump and clean the carb and go from there.Sounds fuel related to me.

 

[12Footer]

Re: It's Me and the 45 again

I concur with fixin. It sounds like classic fuel-starvation.<br />

(" the thing started running rough at WOT so I'd ease back on the throttle and it'd smooth out. Back to WOT and it'd do ok for a few min then miss a bit.")

<br />It could be anything really, but that is chief suspect.<br />Fuel starvation can be due to;<br /><br />low compression,due to blown gasket, worn rings,CC seal. <br />bad fuel pump diaphram or hanging fuel pump check valve,<br />closed or restricted fuel tank vent,<br />air leak in fuel line or fittings.<br />hung reed<br />Loose Carb or leaking carb gasket.<br />If all is ok with those items, you can then rule-out fuel starvation.

 

[Jcrain]

Re: It's Me and the 45 again

Explain the "hung reed" all else is ok. when it cranks, plugs get pretty wet.

 

[12Footer]

Re: It's Me and the 45 again

A hung reed is a reed stuck open. Or it could be a broken reed. Reeds are flapper-valves,that allow air to flow only one direction (open on the intake stroke,closed on the combustion stroke). The reeds rarely give any grief, but have been known to get leaky by no longer seating properly in thier old age, or by metal fatigue, where they break away. They can usually be seen with the carbs removed.<br />A hung or missing reed will usually show up in the compression test.<br /><br />Timing can also cause a simular symptom, but timing on that motor is mechanical and will not/can not move-out of adjustment under normal conditions. If anyone changed the original settings, you'll need a timing light and a pilot, because it has to be adjusted at idle, and WOT underway, under load....Dangerous, but unless you have a test tank and a test wheel, it's the only way to check it.<br /><br />Another thing to check is leaky HV ignition. This will cause an un-steady, usually random miss or stumble,or hickup underway).An easy way to check for this is to run the engine in a pure-dark night. You'll see the arching where it is jumping from HV circuit (coil, plug wire ect), to a nearby ground (motor frame,closest to it).

 

[scotiany]

Re: It's Me and the 45 again

You don't have to replace the fuel pump. You can just buy a repair kit at NAPA for about $10.

 

[Jcrain]

Re: It's Me and the 45 again

I think possibly the flywheel may have shifted. POPS really loud thru the exhaust when trying to start. Fuel pup diaphram was replaced about half a tank of gas ago. Plugs and wires are new. I really wish we had a NAPA dealer within 100 miles of here. Local boat shop wants about$100 for points and condenser. I haven't got to them yet, but am sure they need replaced.

 

[Jcrain]

Re: It's Me and the 45 again

anybody got a NAPA p/n for points and condensers for a 1976 45 model 457HF? Battery ingnition with 2 sets of points and condensers

 

[scotiany]

Re: It's Me and the 45 again

boatingsolutions.com has the points and condenser for about $35(2 of each in kit). Mercury dealer should have flywheel ky for less than $8.

 

[Jcrain]

Re: It's Me and the 45 again

yep, key sheared. Point's actually look real good. Still shiny. Maybe I'll get by with lapping the flywheel and a new woodruff key. Also, I think I'll give it the correct torque this time.<br />Man, before I got this chrysler, all I knew how to do was start up the 90 horse 'rude and rip across the lake. It sure has been a learning experience. My thanks to all who have helped.

 

[fast525]

Re: It's Me and the 45 again

Ran with a sheared woodruff . Not many outboards would do that . Pretty good motor would'nt you say ? Jeff

 

[Jcrain]

Re: It's Me and the 45 again

Dang fine motor. My guess, and I've been dealing with aviation for over 30 years and have seen it happen before, is that the key wedged just good enough to keep it running until I backed off, or maybe it choose that particular time to shear. Who knows?

 

[eurolarva]

Re: It's Me and the 45 again

If that key dosent work you can get the correct one from mercury for 7 bucks. The part number is 28-F92498

 

[Jcrain]

Re: It's Me and the 45 again

Already got a new one...and a spare, to boot!

 

[Jcrain]

Re: It's Me and the 45 again

Already got a new one...and a spare, to boot!

 

[scotiany]

Re: It's Me and the 45 again

Back to the basic question. What caused the flywheel key to shear? I'd like to hear some replies too because mine sheared last summer. Could it be undertorqueing the flywheel nut or something more sinister? BTW, the torque on the flywheel nut is 80 ft/lbs(source-Seloc Manual Appendix A-3)

 

[Jcrain]

Re: It's Me and the 45 again

I am only assuming but the nut that was holding it down had questionable threads. My guess is that I not only did not tighten it enough, but also the threads wouldn't hold what little torque I did put on it.

 

[TOHATSU GURU]

Re: It's Me and the 45 again

There are only three things that could cause the flywheel key to shear on this engine.<br /><br />1) Not being torqued down correctly.<br /><br />2) Metal fatigue on an old key( at least 20 yrs )<br /><br />3) Catastrophic sudden stop.