1965 merc 650 wont start, tries to start but backfires

[anw34]

I just bought a used merc 65hp outboard with electric start I put idle lever all the way forward a pull the choke lever but it tries to start but won't run it just backfires from the exhaust and pops from the bottom Carb. Any thoughts.

 

[Bob_VT]

Re: 1965 merc 650 wont start, tries to start but backfires

Welcome to iboats.

New to you motor? Well depending on what YOU have done to prepare it to start....... read this post http://forums.iboats.com/engine-fre...kening-sleeping-outboard-boatbuoy-158086.html

My recommendations to you:
Do not believe what the seller verbally told you unless it was demonstrated and or documented. (Such as how old or good is the impellar?)
Carbs need to be cleaned and serviced because even 6 month old gas residue can stop your motor from running - Rebuild the carbs.
Check the fuel tank and lines - new E10 fuel will clean the debris out of the tanks and send it to the motor- get a fuel filter AND old fuel lines are no longer good for new fuel.

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

If you have confidence in the motor and the things Bob said have been done or checked, you have to figure out the starting routine.

My cold start is prime the motor (firm bulb), about half way up on the warm-up lever, choke (button on control or lift choke knob on motor) and crank. When I hear the first pop, release the choke button or push the knob down) keep cranking and it starts. Warm starts are usually just crank her over.

The link in Bob's post is invaluable for awakening a motor that's been sitting. And even if you saw her running before you bought her, still some good info. The only thing different for your Merc, is the carb adjustment. Not really different, but that was referring to OMC's so use your new manual for the Merc procedure.

Good luck and Welcome to iboats.

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

Yea I'm new to boat motors have always worked on cars and motorcycles so I know some. But the motor is a 4 cylinder 2 stroke I know all he said was it hasn't ran in about 8 months but last time he had it out the charging system didn't work so he changed the fly wheel. Since I've had it I took both carbs off and cleaned them thoroughly. Put it all back together and now it will fire just won't start n run just wants to backfire. A guy I know said it sounds like something wrong with the reeds. But I do not know where the reeds are located on the motor when I had the carbs off i didn't see them behind the carbs like a 2 stroke motorcycle. So if u guys think it might be the reeds too then could u tell me where they are located and thanks for the quick help guys

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

Forget the reeds. Look at the timing belt/pulley. If he replaced the flywheel, there is a good chance the timing is off.

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

OK that's kinda what I was thinking but I can't find anything on how to check or to time it and cant find which order the plug wires are supposed to go in. Mine start at 1 at the top and in order to 4 to the bottom. Does anyone have any pics or links to that stuff

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

Try this Small Engine Repair Reference Center Home: MERCURY - MERCURY FOUR & SIX CYLINDER MODELS (1955-1965).

Print it quick before it expires.

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

Well I went out and lined up the timing marks and there was no fire so I decided to take the spark plug out of cylinder 1 and the piston was at bottom so I set it to tdc and took the belt of and turned the timing pully 180 degrees and it now fires right up. But now I want to see how good it will run before I take it to the lake is there a way to hook a hose up to it cuz all i have is a container that will hold water up to the top of the little holes on each side of the lower end. The little holes on each side like 6 in a row going up and down is that enough or does the water have to be higher up on the motor

 

[CharlieB]

Re: 1965 merc 650 wont start, tries to start but backfires

Is your flywheel a 2 piece with a bolted hub to outer?

Double check #1 at TDC look at the flywheel timing marks, are they indexed correctly, near the timing pointer?

Suspect the PO installed incorrectly, gave up and sold the motor cause it would start.

It happens.

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

anw34 - Were you able to download that link I sent in post #7? You need a tub/barrel deep enough to cover the anti-ventilation plate on the lower unit to safely run in one. Failing that, you need one of these MOTOR FLUSH UNIVERSAL - Seadog Line 5215001 - iboats or similar. Normally I would say get one here at iboats, but if you aren't getting other parts, etc., shipping isn't worth it. You can find one locally at Wally World.

 

[CharlieB]

Re: 1965 merc 650 wont start, tries to start but backfires

Do you have a set of 'earmuffs'? The garden hose flushing attachment the holds the rubber cups against the inlets.

Finally, found a picture

How to Install Flushing Muffs on a Yamaha Outboard Motor | eHow

 

[CharlieB]

Re: 1965 merc 650 wont start, tries to start but backfires

anw34 - Were you able to download that link I sent in post #7? You need a tub/barrel deep enough to cover the anti-ventilation plate on the lower unit to safely run in one. Failing that, you need one of these MOTOR FLUSH UNIVERSAL - Seadog Line 5215001 - iboats or similar. Normally I would say get one here at iboats, but if you aren't getting other parts, etc., shipping isn't worth it. You can find one locally at Wally World.

I must have used the wrong words to search as all I found was the $50+ kit to winterize an I/O

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

Yes I got it to download thanks for that it was very helpful and i will check at Walmart for it. And the timing is all set starts right up n runs great just gotta get those earmuffs or take it to a lake

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

I must have used the wrong words to search as all I found was the $50+ kit to winterize an I/O

I got those first when I had "kit" in the search. They should use the keywords we all use - muffs or ears. LOL

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

OK well is there a way to know if the pump is pumping water up.

 

[matt167]

Re: 1965 merc 650 wont start, tries to start but backfires

you should have a mist out of the exhaust discharge. If you want a tell tale, there is a plug at the top of the block which you can remove, insert a fitting and hook a hose to. I've heard some of the motors have the provision for the tell tale on the cowl right there, just not hooked up.

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

Item 11 on this diagram is the plug Matt is talking about - Mercury Marine 650 (4 CYL.) CYLINDER BLOCK AND CRANKCASE ASSEMBLY Parts

And my motor does have the tell tale port on the starboard lower cover. So I removed the plug, added an elbow and hose and stuck the hose on the tell tale port. If you add the tell tale, make sure the hose is clear of the flywheel.

When you use muffs, you really aren't testing the water pump. The water pressure will move water through the motor, in fact with a tell tale may squirt before you start the motor.

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

OK last thing I'm trying to figure out is the shift cable hook up. On the motor the part where the cable hooks onto the slide part it will only go back to about the middle of the slide zone and then neutral is almost all the way forward and forward is all the way to the very front of the zone. With the barrel adjusted all the way forward the cable connect to it where about neutral is should reverse be at the back of the slide zone if so then the shift linkage is wrong or the curved rod the connects to it is too short.

 

[GA_Boater]

Re: 1965 merc 650 wont start, tries to start but backfires

First, anw - remove your phone number - Forum rules and the mods don't like seeing contact info in posts.

On the shift cable - What I do is put the shift slide in neutral with the cable off. Spin the prop, it should turn freely in both directions. Then I adjust the barrel until the cable end drops onto the pin on the slide easily and tighten the clamp on the slide. Shift into forward and spin the prop, it will turn in one direction and click as you turn it. Shift back to neutral and check for the free prop again and finally shift to reverse and the prop should not spin.

That method works for me.

 

[anw34]

Re: 1965 merc 650 wont start, tries to start but backfires

Instagram

OK in the picture the mounting pin is all the way in reverse and that's about as far as that thing will go backwards and the black marker marks to the left are the marks where forward n and reverse should be according to the cable adjust. I have the barrel all the way forward and with the lever forward that's where the top mark is where the hole to the pin should be and the middle one is neutral and bottom last one down is reverse. As you can see the pin which is in reverse is pretty much lined up where forward should be and with the barrel adjusted all the way forward and the lever put forward that's where it lines up at