1970 650 mercury spark plug type? And many other ?’s.

[Linkedit]

Hello,

well I got a boat, motor and trailer for quite cheap. 1970 650 mercury. Took a few days get it running. It’s sat for about 6 years. This site has been very helpful In learning about these motors. I’m thankful for that!

So I take it out to lake and run a tank through it. Seems like it’s lagging a bit out of the hole. And top out at 3200rpm. This is low from my understanding. I thought I’d change the plugs run some sea foam through it and run another tank and see where I’m at....

I went to change plugs and saw there was BUHW-2 in there and looked in the manual and it says AC-V40FMM. Is BUHW the similar model? Without the -2?

Will complete compression test this weekend.

Water comes shoots out telltale, but I guess impeller should be done sooner than later anyways.

maybe carb dismantle and reassembled? Is this a difficult task? Seems relatively straightforward I’ve just never done work on an outboard till now.

fuel lines for this old boat.... can just make some with a nipple and zip tie or clamp it on should suffice I imagine as opposed to ordering one for 30-50$?

thanks
probably many more questions as this adventure goes on...

boat is a 16-17 foot vanguard fiberglass, 3 blade 15 pitch prop I believe. And the lake nearest is about 4000’ elevation.

 

[Linkedit]

Well answered my own question with an hour of searching on this site about the spark plug. Seems the wrong plugs buhw-2 were in there so I’ll replace with buhw.
Another thanks to all you knowledgeable folks. I guess I’m not the best with search functions.

 

[The Force power]

Welcome to IBoats :welcome:

There are Sticky notes at the top at this forum that have helpful tips & and many members that have lots of knowledge on your particular motor

Be patience and guys like Chis1956/ Racerone / Fastbullet will tune in

 

[Linkedit]

Thanks For pointing that out. Seems I’ll find plenty of useful info. Should’ve maybe read those first.

 

[Faztbullet]

Anytime you return a engine from extended storage, especially if you have no service history is a compression test. If no problems found then a impeller and carb service are mandatory. The "mechanic in a can" is only good for keeping clean carbs clean and minor residue. On carbs always use new gaskets never reuse old one's and yes you can buy the short hose barbs and zips to replace the fuel lines.

 

[Linkedit]

Will hopefully get the compression test done tonight or tomorrow and hopefully all checks out well and I’ll order some rebuild kits.

when doing the impeller anything else that should be address while I got the lower unit removed?

Thank you for the helpful replies.
I’ll keep ya’ll posted on the progress.

 

[Chris1956]

So a 65HP motor on a 17 footer at 4000 feet? You are asking a lot of that motor. Your prop may have too much pitch.

Anyway, if the compression is good and you get her running well, and she is still at low RPM, maybe a lower pitch prop will help.

 

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Got 112-119 psi for my compression. Is this what I should be expecting?

I do plan on getting a smaller prop to try out. Given we did have four of us in the boat and two cans of fuel. Might be a little bit of weight for a little boat.

thanks again any google search I do I end up at this forum....

 

[Chris1956]

That compression is fine. Have you ever run that boat on that lake with that prop, successfully, before?

In the old days, we had a 650 on a light 16 footer and would use it to water ski.

 

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I have not ran it on that lake with any success. I guess I’ll order some rebuild kits and have some fun learning more about boats.

I spoke to a friend who said when he rides on this lake he needs to go down three pitches in props if he wants to pull skiers.... so I’ll definitely look into a 13 pitch prop, I believe I’m running a 15 right now.

Is it normal when I put it in forward the lever must be pushed forward nearly 80% before the throttle begins to rise? Got a few days off so I’ll play around a little . Much to learn for this fella! I did manage to get a service manual for this engine from my wife’s great uncle. He had it kicking around Still, and found out this engine had been rebuilt quite a few years ago.

I’ll get some kits and do carbs and impeller and repot back on how I’m doing. And probably have questions by the time I get there. Lol.

thanks.

 

[Chris1956]

Merc controls have neutral at the 12 o'clock position. Forward at idle is about 10 o'clock. Acceleration starts at 9:30 or so.

As long as she gets wide open throttle, which you can check, the control is working properly.

 

[Linkedit]

Wow thanks.

Seems like the operation is there then.

And looks like throttle is opening all the way When I peeked inside carbs.