1990 70hp johnson

[scsdiver]

i have two issues. i am fairly sure i know what one of them is but i will deff take any other suggestions. my outboard sat for 2 years and i am pretty sure the water system is clogged or a bad thermostat. it had dirt dobbers and wasps nest built in it and i am sure they didnt help the situation. i already replaced the water pump and all the seals and water pump cup in the foot. it does spit water out if you rev it a little but no steady stream out of the pee hole. i bought a thermostat and gaskets and i also bought exhaust manifold gaskets to hopefully blow out anything that may be clogging it. i am going start with the thermostat.

second issue is seems to have a high idle. it runs fine starts right up but i think the idle is way to high. i do not have the rpm gauge hooked up yet so i dont know a exact number. i have adjusted the thottle linkage down the the physical limit of the idle arm and that still does not seem enough. any suggestions or idea's here?

 

[Pappy]

For the idle, you will have to retard the timing in addition to dropping the arm back that the throttle cable hooks to. Am thinking you need to invest in a manual. There is a complete sync&link procedure that has to be done and re-adjusted when you change any one of the adjustments. Too much for me to try and explain it all to you here.......would have writers cramp.
As far as the overheat goes try compressed air back through the overboard indicator hose and clean that out first. Second, did you purchase a complete waterpump kit complete with cup and plastic housing? If so did you glue in the o-ring between the cup and housing? That should only have about 4 points of adhesive on it if you did. A common mistake people make is to completely coat that groove with adhesive and in doing so you are covering a vent hole that is there to help purge air from the pump assemble so that it will develop max volume and pressure.
Try removing the 4 screws holding the thermo cover on and pull the thermo assembly. Leave it all off and start your engine and see is there is a significant amoung of water overflowing that area. There should be a decent flow and alot if you blip the throttle.

Another thing to look for. If you used a complete OEM kit there should be instructions in there to update your cooling system. Kit would have come complete with new conical and straight springs, etc. It pays to buy OEM as I think your engine was in the years that needed the cooling update.

 

[scsdiver]

For the idle, you will have to retard the timing in addition to dropping the arm back that the throttle cable hooks to. Am thinking you need to invest in a manual. There is a complete sync&link procedure that has to be done and re-adjusted when you change any one of the adjustments. Too much for me to try and explain it all to you here.......would have writers cramp.
As far as the overheat goes try compressed air back through the overboard indicator hose and clean that out first. Second, did you purchase a complete waterpump kit complete with cup and plastic housing? If so did you glue in the o-ring between the cup and housing? That should only have about 4 points of adhesive on it if you did. A common mistake people make is to completely coat that groove with adhesive and in doing so you are covering a vent hole that is there to help purge air from the pump assemble so that it will develop max volume and pressure.
Try removing the 4 screws holding the thermo cover on and pull the thermo assembly. Leave it all off and start your engine and see is there is a significant amoung of water overflowing that area. There should be a decent flow and alot if you blip the throttle.

Another thing to look for. If you used a complete OEM kit there should be instructions in there to update your cooling system. Kit would have come complete with new conical and straight springs, etc. It pays to buy OEM as I think your engine was in the years that needed the cooling update.

Pappy thank you so much for the details! i did buy a manual and ill be honest i have been working on the boat and have not touched the motor but i will be starting on it tonight. i bought a new thermostat that even if it isnt bad hey what can it hurt right. I bought the upgraded cup and the impellor as well as a seal kit for the lower unit. i was very certain to make sure nothing got in the way on the hole as i had read that so hopefully that is not what it is. the previous owner had the motor serviced every year and had impellor replaced and other serviced. so im really hoping that since it was just sitting it is just clogged up. thanks again for the info ill let you know how things turn out tonight.

 

[whiteboots16]

Man I have the same motor. My idle is doing the same thing. Also it seems like I dont have all the power the motor is capable of. Where did you get your manual from?