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1972 Mercury Model 650 65Hp two stroke throttle and gear shift cable adjustment

tgeers

tgeers

Member
I have this wonderful 65 hp mercury outboard. The main problem is it is 50 years old. Both the throttle and gear shift cables broke where they pass through the transum to the motor. I replaced them with new cables but now the motor, when on the water, will spudder periodically. Not completely understanding the interaction between the two cables has led me to believe I'm not doing something right. There could be other issues causing this. Could someone point me in the direction of diagnosing the cause? I appreciate the help I've received here in the past and hope your advise will help me again. Thanks
 
Post the results of a compression test.-----And have you changed out the water pump impeller ?-----This is the first year for the 3 cylinder 650.----Issues with top cylinder are common.
 
Sounds like the new cable is shoving the idle setting too low. Try adjusting the low speed stop a few turns in.

Jeff
 
racerone and Jeff,
Thank you very much for your rapid replies. I currently do not have a compression tester, however I did change out the spark plugs and noticed the #1 plug was burnt looking while the other two looked good. It has the type of plugs made for outboards. It is a new boat for me, so I have a lot to learn about it. I did have it up to 30 gps/mph when it wasn't studdering/missing? Therefore I assumed the compression was good. If the compression is bad in that cylinder, what am I looking at then? It does have a new impeller that works very well.

Jeff, I will try your suggestion.
BTW, the boat is a 16.5' starcraft V hull.
You guys are a great resource for folks like me. Thanks again
 
Hey Guys, Thanks again for your responses. I have borrowed a compression tester from my auto mechanic. As soon as I get to use it, I will post the compression results.
Thanks again
 
Hi All,
I have used the compression checker on all three cylinders and surprisingly each cylinder tested between 120-130 psi. I assume there would be no problem in that area.
By way of background, I am a fisherman, fishing the Ohio river near Lawrenceburg Indiana. Several other fishermen have recently commented on their boats running rough due to bad or dirt in the gas. Taking their advice, I've added some seafoam to my gas. I did check my fuel pump and it looked clean. I'm reluctant to explore the two carbs, so I'm hoping the seafoam will do the trick. If you think there is anything else I should try or should know about using seafoam, please let me know. I appreciate all the comments you have already taken time to offer.
Tony
 
A blockage in a carburetor means less fuel going in.------And less oil.------It is important to have clean carburetors in any motor.
 
Point taken. I plan to run a tank of gas/seafoam through the engine. If that doesn't help, then my only other alternative is to see if someone will look at the carbs. It appears that someone removed the fuel filter. Or I just can't find it. Around my area no one wants to work on anything with carbs. The best boat mechanics only work on newer engines. I've wrenched on 700hp race cars before and know that carbs are in a world all their own. Here's hoping the seafoam works.

As mentioned in another post, I really do appreciate the time and help you put in for boaters like me.
Tony
 
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