70 hp johnson

[buckw3]

i have a 86 70 hp johnson that i just put a used vro pump in. it will now idle and go slow but when i try to plane out and speed up it bogs down. if i push the primer on the key it will at least plane out but not get up to speed. does this sound like a carb problem?

 

[JB]

Re: 70 hp johnson

Sounds like a fuel pump problem to me, Buck.<br /><br />How did it perform before the used pump?

 

[OBJ]

Re: 70 hp johnson

Using a used VRO pump is not a good idea. It's used 'cause someone took it off their engine for a reason, most likely it was broke. What color is the fuel outlet on top and how many wires is in the wire harness from the pump?

 

[buckw3]

Re: 70 hp johnson

there is 3 wires in the harness and the fuel outlet on top is brown

 

[buckw3]

Re: 70 hp johnson

before the change in vro pumps it wouldn't even run without pumping the ball

 

[jayboy70]

Re: 70 hp johnson

Good chance that the other replys are right about the pump however your symptom sounds like what I had on my 1984 Johnson 60 when the high speed jets get dirty. Its almost impossible to keep the dirt daubers out of my engine compartment so dirt happens. It will run just fine for awhile after a good cleaning job then all of a sudden it will run good slow but loses power at the top end. Another good cleaning job and works OK again. Been through that several times in the last 3-4 years. Try cleaning first!<br /><br />PS- My primer made mine work too at high speeds.

 

[OBJ]

Re: 70 hp johnson

Three wire harness and a brown outlet.....something isn't jiving here. I believe the new pumps have a brown outlet but are 4 wire in the harness. Maybe ya' got one that's pieced together?? Maybe one of the other guys can help on this. But it's still my opinion that using a used pump is not a good idea. <br /><br />And I would consider a carb overhaul also as suggested by jayboy. Check all the fuel lines are still pliable and have not gotten stiff. Replace any that have and make sure the fuel line connections are tight.<br /><br />Keep us posted....thanks.

 

[buckw3]

Re: 70 hp johnson

sounds good i will try to clean the jets in the carb. by changing the vro pump has seemed to help quite a bit. when it is out of the water it seems to run allright just once in the water no good the primer button helps it plane out but it still won't reach top speeds even doing that..... keep you posted

 

[seahorse5]

Re: 70 hp johnson

The 3 wire pump was not one of the better ones. A 4 wire pump with a gray or with a replacable fuel out fitting is a lot better.<br /><br />I'm with the others, it sounds like a pump problem. You also have to change out the pulse limiter to the blue one. Your motor may have a black one.<br /><br />Since the primer activation helps the motor run better, you have carb problems also.

 

[Dhadley]

Re: 70 hp johnson

I agree, I'd be very cautious of that pump. I'd use the 4 wire pump like Seahore said.<br /><br />However, if activating the primer helps, that indicates a carb problem. If the pump wasnt working and not supplying fuel, there would be no fuel available to the primer or the carbs without manually pumping the bulb.<br /><br />Claening the jets may or may not solve the problem. To clean the carbs correctly you need to soak the carb body and bowl. <br /><br />Remember, pistons live on fuel. Without fuel (which has the oil in it) pistons tend to revolt.

 

[rodbolt]

Re: 70 hp johnson

hello<br /> I will go with the rest. I think the last of the 3 wire pumps was in the early 90's. if your using this pump to supply oil as well as fuel your flirting with disaster. a replacement VRO costs the same with or without pistons. if you can hit the primer and gain RPM you have some clogged main jets which require a carb dissasembly to correct, carb kits also cost the same with or without pistons. do a compression test to verify engine condition.<br /> good luck and keep posting

 

[DHPMARINE]

Re: 70 hp johnson

Being a small shop,I don't see many Vro pumps with oil failure.usually leak gas out the top of the unit.And we replace the pump as oppossed to trying to rebuild.<br /><br />But if the motor now idles,but won't do high speed,pump the primer bulb and see what happens.If it runs okay,the fuel pump side of the pump is bad.<br /><br />I would replace the vro with a new one,and enjoy boating.As far as I know,the number of wires indicate a newer pump,but older pumps can be rewired to have more wires.This gives more warning sounds,and maybe an RPM slow down.<br /><br />DHP

 

[DHPMARINE]

Re: 70 hp johnson

buckw3 While you are working on this motor,why not fix the gas supply with 50/1 to be sure?<br /><br />DHP

 

[buckw3]

Re: 70 hp johnson

i cleaned the carbs today and noticed one of the carbs the throttle bar that hooks them all together was unhooked from one of the carbs would this be the problem. i also checked the plugs and noticed they were a little white like they got hot would it hurt to run mixed gas and the oiler or will that be too much oil. also what is the best plug to run i have champion ql77jc4 in right now but am going to pick up some new ones

 

[OBJ]

Re: 70 hp johnson

Buckw....run premix in addition to the VRO until your sure the oil in the oil reservoir is being used. And make DARN sure the alarms for the VRO system is working. Running premix won't hurt. When your sure the pump is working, take it off premix and do a decarb.<br /><br />The QL77JC4 spark plug is the right plug. Set at .030. Setting at .040 may give a little better idle.<br /><br />Check the engine for over heat next time you run. Second possibility is your not getting oil from the VRO...so be REAL careful that the engine is getting oil. <br /><br />Keep us posted....thanks.

 

[buckw3]

Re: 70 hp johnson

hello all. I ran the boat today after i checked the carbs and replaced the plugs. it ran better, it picks up to almost full speed but i still press the key in to get it to full speed. what do i do next. is it the vro pump, can i spray some cleaner in the carbs. could one of the gas lines have a pin nole i cant see please help