1979 115 hp Thermostat replacement

[breezland]

I am replacing thermostats on johnson 1979 v4 seahorse 115 hp. i have trouble reaching the bolts holding the housing for thermostats. i have removed the plastic water sheild around the bottom of engine but i cannot seem to get rachet on the bolt too well because it is very old and beginging to strip. How can i remove the bottom part of the enging housing so as i heat bolts and get a rachet striaght on to the head of bolt. or is there any easier way to do this that i may not be aware of.

 

[bill giffear]

Re: 1979 115 hp Thermostat replacement

CRABAHALIC,I wouldn't put ant heat on the bolts,because some of the thermostat covers are <br />plastic,also your thermo/bypass underneath the covers are plastic. try cutting a box wrench in half and tap with a hammer,thats what I did to remove the bolts. bill

 

[breezland]

Re: 1979 115 hp Thermostat replacement

I am assuming the thermos are bad because water shoots out as soon as engine goes on and i was told by mechanic that it was running cold and it runs very rough when i first go out. Whereas before this occured it took about minute or so for water to start shooting out. Since i may have a very tough time gettting the thermostats replaced is there anyother way around this problem? Could it be the thremostats are not bad?

 

[DJ]

Re: 1979 115 hp Thermostat replacement

crabahalic,<br /><br />You cannot romove the lower pan without removing the powerhead. However, you can loosen all the bolts that hold it up and get about an inch or so more room. Enough to get a SIX point socket on it.

 

[Solittle]

Re: 1979 115 hp Thermostat replacement

I just finished this job on my twin 1988s (basically the same as yours). It can be done but it is a bit of a pain. Yes you can loosen the pan which may help. Much depends on the wrenches/sockets that you have. I used an open/box combo going in from both the bottom and the top. I also used a 1/4" socket with a universal to get to the lower center bolt. I also used a long extension which helped. Neighbor also lent me a 3/8" drive 1/2 socket with a universal on the end of the socket (combined rather than two pieces - Craftsman).<br /><br />There are several tips available to you if you use the this forum's search function.<br /><br />Another thing, when you go to put it back together use the gasket sealer (see posts under Search) and be careful to get the gaskets, stats and relief valves and springs in the correct order. I used rubber bands to hold the assembly together when putting it back in. <br /><br />Putting it back in is a two person job (was for me at least). One guy tries to hold the assembly in place pushing against the outer cover to compress the springs of the relief valves - while the other guy (me) attempts to get the first bolt started. A bit of cussing helps at this point. If the right words are said the bolts will grab the threads and you are home free - - don't forget to get the rubber bands out after you get the bolts started though.

 

[breezland]

Re: 1979 115 hp Thermostat replacement

I tired to do the best i could i even cut holes in the bottom plate so i could fit a rachet in & pull the bolts out. After trying every type of wrench, one visit to Sears, checking this page numerous times and even visiting a marine shop for a dry run i finally just took it in to the shop and am having the pro's do it. i got one bolt loose but i could see diaster on the horizon. some jobs don't seem to pay to do it yourself and this was one of them. Thanks everyone for your help.