1970 60hp Evinrude outboard

So we just recently bought a new (used) boat, (winner cobra?) model number on the boat is 701536 WH, if anyone can fill me in there it would be great as im not sure of the year. The motor is a 1970 60hp Evinrude which is currently running (just not great). I have changed the spark plugs out, cleaned out the 3 carbs and fiddled with the fuel as far as lean and rich. in neutral it runs excellent you can hear it purr like it did in 70 first year on the lake, but as soon as were in water and throttle up it sounds really bogged down, we cant even get it up on a good plane im sure a 60hp motor is more then enough to push this boat pretty quick, i have messed with all i have knowledge of. Compression is good in all three cylinders were getting about 110psi even on all 3. if anyone has suggestion to get this thing running great all thoughts would be great. also sea foam? was told i should definately run it through so ill be giving that a try tonight.

one last thing is i was told my prop may be too deep for the boat? not quite sure what that means. I am a mechanic (on land) i have decent knowledge of engines, but boats are a whole new deal for me. all help is welcomed!

Re: 1970 60hp Evinrude outboard

What is the compression on the cylinders, have you checked spark, should jump a 7/16" air gap and be bright blue.
Could be you are not running on all cylinders.
What size prop are you running?

Re: 1970 60hp Evinrude outboard

Ill reply to the best of my knowledge, compression is testing at 110 psi in all cylinders, spark looked good we tested each cylinder by itself to make sure they were all firing and they all *seemed* to be firing correctly. top cylinder seemed to run better the cylinders 2 and 3. and prop size im thinking its a 14x11 but im not positive. the blades are angled very steep.

Re: 1970 60hp Evinrude outboard

Compression should be Ok. Your carbs have fixed high speed jets, nothing to adjust. You said you cleaned the carbs, did you remove the high speed jets and make sure they were clean?
You might pull the flywheel and dist cap and check the point setting.

Re: 1970 60hp Evinrude outboard

Currently using the evinrude site for all my breakdown views. with the highspeed jets how difficult will they be to pull off to clean? Can the prop cause the boat to bog down if it is to large? what are the downside of that and should i look into getting a smaller prop or prop with a more shallow blade angle?

Re: 1970 60hp Evinrude outboard

The high speed jets are in the bottom of the float bowels behind the 7/16 drain plugs. It takes a special screwdriver to get them out. They are made of brass, and can be damaged trying to remove them with a screwdriver that does not fit properly.
To large of a prop can cause the engine not to rev up properly, but I would make sure the engine was running properly before I would buy a new prop. Can you ask the person that sold you the boat and ask them if it ever ran properly with the prop that is on it?

Re: 1970 60hp Evinrude outboard

When we bought the boat the last owner hadn't had it in water for almost 2 years, said he had winterized it every year. But for 600$ it was a deal we couldnt pass. We have had to lake bound twice now first time Dead battery 3/4 mile from dock (forgot to charge it the night before) But we had it running pretty good. The problem isnt in low speed we can chug along just fine. As soon as i hit the throttle it seems to sputter a hair and doesnt quite want to do it. After that we cleaned the carbs checked compression, cleaned the fuel filter and lines and made sure we were running fresh fuel. Same problem when we went out it doesnt sputter but it doesnt pick up and go like it should, it seems very bogged down.

Re: 1970 60hp Evinrude outboard

You should also check if this is a fuel related problem.
Check if your fuel pump works correctly. Pump the primer bulb when the engine is bogging down and see if it makes any difference.
You could also check if your fuel lines are not degraded/blocked, ethanol blended fuels are not kind to the old rubber components.

Good luck, Peter

Re: 1970 60hp Evinrude outboard

Well, lemme tell ya something. I have lots of grey hair, and much of that came from trying to make those 1970 60hp motors run properly, even when brand new. The #1, most important thing to do is deep-six the original surface gap spark plugs and replace them with Champion L77JC4 or QL77JC4. We gapped them at .040" but many now say .030". So....have the plugs been changed yet?

Only after that should you be messing with anything else.

EDIT: Oops....I typed the wrong plug number. Should be right now.

Re: 1970 60hp Evinrude outboard

Could fuel cause the issue? And we seem to be burning through fuel pretty quickly.

Re: 1970 60hp Evinrude outboard

Yes we have changed the plugs but those are not the.plugs were using they are gapped at .030