Motor trouble...need help?

[9095k]

I have a 1989 mercury 70 hp 2 stroke. I just got it has been sitting for three years now it was looked over and cleaned up by a local marine guy and when it was in drive way it ran great. ....well since putting it on water it has had a couple issues. .1 the motor has to be throttled about 30%to start and run and when you put in g gear it instantly dies. ...but sometimes it will go but it takes about 12 attemptsbefore it works. ....well if it does run it seems to run fine for a while but all the sudden it will bog down....then die. ..but will run after that. ...I'm very confused I really appreciate some help to get started it seems to be getting gas (the tank is full and the pump ball is solid)...

 

[Brooky]

Old gas?

 

[gm280]

:welcome: aboard 9095k. Glad you could join us...

It sounds to me like a good time to rebuild the carb and install a carb kit. Looking at your carb break down, it look basically simple and easy to rebuild. So that would be my first option... JMHO!

 

[9095k]

It is new gas. ....but I will look into rebuild of carb ...I've been told that sea foam can help. ..is that the best product available?

 

[DavidMoore]

I will second a carb strip clean and rebuild.

Other things to check I'm not expert but have experienced the engine bogging down and dying, all kinds of issues can cause this so here is my little list of things to check starting with the easy and cheap moving onto more difficult and expensive.

Arrow on primer bulb pointing in the direction of flow and pointing upwards, at least not pointing to the floor. -- (this was my problem and the last thing I checked :facepalm
Spark plugs, nice and clean or all black and oily?
Fuel filter clean?
Fuel hoses not swollen and restricted from inside?
Carb synchronisation. Check the butterfly valves all open together and by the same amount.
Carb strip clean and rebuild
Fuel pump rebuild (checking the hole going to the crankcase is not blocked)

Note I suppose you are throttling the engine to 30 % using the fast idle lever?, if so it's the normal starting procedure + a little choke. let the engine warm up a few minutes before putting it in gear.

 

[Brooky]

It is new gas. ....but I will look into rebuild of carb ...I've been told that sea foam can help. ..is that the best product available?

I'm a big fan of seafoam. The first time that I used it was on a snowblower that would barely run. After a good seafoam treatment, it purred like a kitten. Botton line is that it's an easy and cheap thing to try first. Every other year or so I disconnect my gas line from the main tank and drop it in a fuel can with a 70% gas, 30% seafoam mixture. Perhaps even 60/40. Run it through the engine for a while, and then let it sit for a couple of hours and do it's magic. Then run the engine again. Hook the gas line back up to the main tank and dump the remaining mixture in there. This has kept my 2001 60 hp 4 stroke running as smooth as a sewing machine.

 

[9095k]

I have a new fuel line. ..and I will check to see if arrow is pointing up. ..I put a can of sea foam in gas it's a18 gallon tank so I put all in it. ...I did a spark test and they all passed but I'm replacing plugs today when I get off work. ...I will also change the fuel filter today. .I really appreciate the help

 

[9095k]

Well I'm still at a lose. ...the spark plugs are new and have spark. ...I tried putting fuel in the spark plug hole and still no fire. ...I sprayed ether in and no fire. . Is it possible the coil assembly is not producing enough fire?

 

[DavidMoore]

I've read before that a plug that fires outside of the engine might not fire inside but never experienced it myself.
The only real way of checking would be to use a spark gap tester but to be honest I doubt it's your plugs.

What exact engine do you have? Due to the year and HP rating I am assuming it is an ELPTO (3 cyl) engine

It's recently installed to the boat.
Did the engine come with a remote control, the correct remote control for a 3 cylinder ELPTO would have a fast idle lever on top, the key switch would have a label that states states push to choke, and a kill switch?

What else (except the ignition) would cause no fire.

The kill switch on the remote control is in the run position?
The engine really cranks over nice and fast?
Is the throttle cable linked up correctly, it's not by accident holding the carbs open, if it is its not going to fire.
Remove the air silencer, with the engine in neutral and the fast idle lever down check the carbs are closed, raising the fast idle lever will open them slightly.
With the fast idle lever up you should not be able to put the boat in gear. Lower the fast idle lever and put the engine in gear at wide open throttle, check all carbs are fully open.
Try to open the carbs just a little, so you can just slide the shank of drill bit (around 1/8 inch actual size is not important) between the butterfly valve and underside of the carb throat in the middle carb, then with the same drill bit check the other carbs are open the same amount.

If all the above checks out, I think, after getting the service manual for your engine, a carb strip clean and rebuild is your way forward.
The service manual will guide you through this step by step + it will be one of the best investments you ever made.