Water tube to water pump on Johnson RD-18

[sjaspers]

I am putting my gear case back on the lower unit. The parts book shows a little O-ring in the area where the tube meets the pump. My manual gives no instructions exactly where this O-ring goes and I do not see any groove or place to put it. Do I just put it on the end of the tube and insert it into the pump? Is there suposed to be a seal of some sort in this area, or is it just a friction fit?

 

[Paul Moir]

Re: Water tube to water pump on Johnson RD-18

The only O-rings I can think of are the driveshaft top o-ring (often shown floating around the top of the water pump), the shift bushing o-ring which seals the gearcase, and the o-ring used for the longshaft extension which goes inside the 5" water tube extension (which you shouldn't have).<br /><br />Can you tell me the p/n of the o-ring?

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

Thanks for the reply Paul. My parts book shows an 0-ring part number 303059 now 339543 according to the dealer. It is above the grommet in the picture. (I do not remember seeing the grommet now that I am writing about it, I will have to check that too). The last thing I need is water spraying arround in the lower unit housing.

 

[Paul Moir]

Re: Water tube to water pump on Johnson RD-18

That is the driveshaft o-ring then. Just make sure it's good and put a light coat of grease on the splines.<br /><br />Just to forewarn you, there is a hole in the water tube part way up the lower unit housing - it is supposed to be there. It provides some cooling to the midsection (although the top gets very hot).

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

Thanks. I am correct in assuming that no sealant is needed on this junction (gear case to lower unit) right. I think that I have read that a number of times but hey, why not be sure while you are available. I think that I am very close to trying this thing out. I need to put the needles back in the carb., hook up the gas can and start pulling my shoulder apart. <br /><br />That reminds me. The high speed needle was more rounded than many I have seen but did not show signs of being worn down. Were these needles sharp to begin with? The low speed needle is tapered to a point like most others I have seen.

 

[Paul Moir]

Re: Water tube to water pump on Johnson RD-18

The idle needle is sharp, but the high speed one is very blunt. That's normal.<br /><br />No sealant between the lower unit and gearcase. Manual calls for a little sealant between the lower unit and the wear plate, but not between the wear plate and the water pump housing. I know a lot of very good techs do not bother with that step though, and I'm also nearly certain the factory didn't either.<br />However, the little webs that support the wear plate are often found broken & bent from trapped water freezing in them. So I do use sealant in the hopes of preventing that. The broken and bent webs don't seem to hurt anything though.<br />Use a little sealant on the bolts and screws though to prevent corrosion. They will come out much easier next time.

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

I put it all together and tried the shift mechanism to see if the connection was good. It would not go into the forward gear. I will have to take it off tomorrow and spread the connector a little so that the rod of the gear case will go farther into the connector. There is always something to complicate matters. I think the bolt might also be stripped on the connector. More fun.

 

[Paul Moir]

Re: Water tube to water pump on Johnson RD-18

Did you rotate the prop a bit? It will not go into forward if the dog ears happen to align with the gear ears.<br /><br />If that's not the problem, then make your adjustment at the shift handle itself rather than fooling with the connector. There are two locking screws that will give you some play.<br /><br />The connector bolts strip rather frequently due to the fact they're only into a couple threads of brass and people often overtorque them. The connector is still available from the dealer for very little money. But that should not affect your shift adjustment.

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

Yes I did rotate the prop. The gear selection is just a little bit off. I get reverse in neutral and neutral when the gear selector is in forward. I observed the shift rod connector as I changed the gears and there was some give to the connector due to the stripped bolt allowing the rod to slide. I will find some time today during a work break to steal a connector off a 1959 Lark 35 that is appart and replace it later. That is the joy of having a few motors hanging around. I love working on this stuff with my students. It is too bad they are now gone for the summer.

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

The connector is changed and the gears are working properly. As a rookie I have to learn a few things the hard way. Having taken the connector out I had a better look at it and realized that I did not have the rod in all the way. The bold has to be fully removed before the shaft is able to be properly inserted. The bolt is then half the anchor as it fits into the groove of the shaft, rather than just a tightening device. Another mistake I will not do again.

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

Just an update for those who have helped me through this project. The motor has been rebuilt! I can not get the thing to fire yet. I will be looking at the timeing and magnito to look it over tomorrow to see if that is the cause. I sure look forward to hearing this thing run.

 

[sjaspers]

Re: Water tube to water pump on Johnson RD-18

It is running!!! Thanks all!!!