v4 crossflow bubbleback: looking at a thermostat job: what to order?

overheat alarm sounds at mid power, not at idle, and little or not at all at high rpm...

took the heads off and the passages are clean and the flow diverters are in place an in good shape. will take the foot off and re-check the water pump, but it's new with only a handful of hours on it and the telltale is strong, as is the flow out the two water-exhaust holes under the powerhead tray.

so i'm afraid i'll have to do the knucklebusting job of replacing the thermostat on a bubbleback. yuck.

anyhow, for those who have done this job before, should i just order every part that sits under the thermostat housing including the spring?
or just the thermostat, and gaskets?

of course, any tips on making this job easier are welcome. i build my own race car engines, so i'm pretty comfortable with tools, but i'm no better at working in tight spaces than anybody else.

-peter

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

Unless you're really handy with tools, the best way to get at the thermos on that mtr is to pull the power head.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

boobie said:

Unless you're really handy with tools, the best way to get at the thermos on that mtr is to pull the power head.

Click to expand...

thanks for that tip. i've got a hoist, so i'm game for hoisting off the powerhead.

anything else? should i order the whole kit and kaboodle or just a thermostat?

-peter

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

should i order the whole kit and kaboodle

Click to expand...

Whole kit.....

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

This thread has good info: http://forums.iboats.com/johnson-ev...sing-removal-question-576694.html#post3962214

Buy the whole kit so you don't have to do it twice because something you reused leaks.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

You can definatley change the t stats without pulling the power head.

something that has made it easier for me is different bolts than the original ones. The originals were 7/16 and the shop I buy the parts from gave me either updated ones or just ones they recommed because its easier to fit a swivel socket that is 3/8 vs a 7/16 in to the t stat housing area.

the bolts are the same length and thread size but use a smaller 3/8 head.

good luck

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

I may be a bit late chiming in, waiting for the experts. I would get all of the gaskets, thermostats, grommets, pressure relief valves & springs. When I did the job (1986 110HP), I drilled out the hole in the valve body a few thousandths. I also notched the pressure relief valves just a smidge to allow bleeding of the water (recommended by "someone"). I pulled the "rear cover' from the cowling in order to access the thermostat cover bolts from below, as well as holding everything in place on re-assembly. I modified a few box wrenches so that they could undo the t-stat cover bolts (that's the hard part). For re-assembly, I coated the valve body gaskets, thermostat gaskets with sealant and sandwiched the whole mess together overnight so that I could install it as a package. This left only the springs and pressure relief valves as the problem on re-assembly... and it was a problem. But, I would consider it less of a problem than removing the power head (never done it, so how would I know?). I definitely needed access from above and below to do the job. I also used twist ties to hold everything together while the bolts were installed. Pics hopefully will work....1st pic is as the assembly looks as removed. 2nd pic is the board I drilled out so I could sandwich everything "glued" together, 3rd pic is sandwiched assy, 4th pic is ready to slide in. Again, problem is keeping the springs on the pressure relief valves as the bolts are inserted and tightened. 2 hands in addition to your own might help.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

I tried dropping the lower cowl, as per OMC instructions. That didn't go quite well as planned. And damned if I was gonna pull the power head just to change T-stats, so's I broke out the grinder w/metal cutoff wheel ...

Ain't nothin a redneck cain't fix with duct tape. But seriously, I made a purty clean cut. Plan to reattatch using rivets'n a lil 'backerboard' of sheet alum or ss.

Back to the subject at hand: Yes I would buy the entire rebuild kit. Worst case you use all the parts, best you wind up with a couple spares ...?


edit. That block where the grommets go, and where the relief valves seat, is made of "Bakelite". Not metal. Don't get too aggressive in your cleaning methods & accidentally break it. Easier than you might think. Trust me ...

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

Where do the round thermostat gaskets go?

Do they go between the bakelite blok and the t-stat or between the t-stat and engine housing? I have seen diagrams showing both places.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

Pat2009 said:

Where do the round thermostat gaskets go?

Do they go between the bakelite blok and the t-stat or between the t-stat and engine housing? I have seen diagrams showing both places.

Click to expand...

Per my factory service manual, the round gaskets go between the bakelite valve body and the thermostat, pic attached (turn head sideways to view). When I did the job, I found that the round gasket thickness was such that when the thermostat was installed, it caused the adapter gasket to be raised up off the valve body by "a bit", enough that it worried me. I guess they want it thick enough so it compresses and seals.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

Thanks. The raised adapter gasket is what caused me to question the proper order.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

I wonder if the OP ever got it repaired ??

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

probably not
its a real *&*^%^&d of a job to do ,but once you drop the pan or lift the powerhead its so easy.
i think a nice split lower pan would make life very easy, or a simple back door to get at them wouldnt hurt.

I wish everyone would say when they have completed the job,its like an unfinnished story and is a bit unfair to
those who were trying to help them solve the puzzle.


phill

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

Well spoken.....

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

V153 said:

I tried dropping the lower cowl, as per OMC instructions. That didn't go quite well as planned. And damned if I was gonna pull the power head just to change T-stats, so's I broke out the grinder w/metal cutoff wheel ...

Ain't nothin a redneck cain't fix with duct tape. But seriously, I made a purty clean cut. Plan to reattatch using rivets'n a lil 'backerboard' of sheet alum or ss.


...

Click to expand...

Do you have a picture without the duct tape, so we can see the cutout size? Do you have a picture of the completed job using rivets or whatever you ended up doing?

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

I guess V153 was not around to answer. I went ahead and did mine his way to completion (not temporarily duct taped), you can see the details toward the end of http://forums.iboats.com/johnson-ev...replacement-1990-115-v4-crossflow-617693.html with pictures.

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

My apologies for not answering fast as you like. Forgive me. I run a small business and thankfully have been very busy lately.

My cutout is roughly 6 1/2" wide by bout 2 1/2" high. Lil taller than it needs to be but just wide enough. Sorry it's raining & I ain't goin out to peel the tape off right now ...

Re: v4 crossflow bubbleback: looking at a thermostat job: what to order?

just saw your pics on another thread Klink
you done a great job with the cut out, and i think youl find a lot of people copying that idea ha ha
well done,
anything that makes it easy to get those b&%^$ out is a good one

phill