Head Rebuilt - What Next?

[mreinsmith]

Force 125

So my brother and I finished rebuilding the Head, we had to reset the head cover as well because of a leak around one of the plug holes (what a time consuming PIA)

Now our compression is 120 across the board! and we took it out to the lake over the weekend and it runs awesome. No problem starting and its shifting into forward and reverse with great confidence. it was nice.

Of course, there are some exceptions.

1 - It's only getting up to 3500 RPM @ WOT. We double checked all the adjustments at the dock. (the specs say 4500 to 5500 rpm, btw)

2 - When we first started it after reseting the head cover, it was missing pretty fiercly. So much so it would throw the hold engine to the left. but then after about 10 of these it stopped. Then only once while we pulled away from the dock it happened again, but then stopped and gave us no further trouble.

So, as time allows, we are going to take the following steps. (maybe even just over the winter)

1 - check the timing
2 - rebuild the carbs
3 - Replace the reeds (or simply replace the gaskets depending on what we find)
4 - check/repair the ignition system

I just want to keep my head straight about all this. So if anyone can add thoughts to this plan please do so.

As usual, thanks to everyone for their help so far.

A special "shout out" goes to Frank for all of his help in getting us this far.

M

 

[Matthew A.]

Re: Head Rebuilt - What Next?

Check to be sure the linkage for the carburators is allowing the throttle butterflies to open fully for each cylinder. I wouldn't mess with the reed valves unless you are certain you need too. Also be sure timing is at full advance while at WOT.

 

[mreinsmith]

Re: Head Rebuilt - What Next?

We checked the carbs while in the water and synchronized them (the lower one was a touch off)

The timing is definately next on the list. Then I'll check the reeds to see if they are still in good shape and make my decision based on that.

if you have any other ideas, let me know.

Thanks for your input

M

 

[stoops]

Re: Head Rebuilt - What Next?

2 things I found effect the RPM's, first...prop size. I changed from a 13.25 - 17 to a 12.125 -21 which lowered the RPM's from 5000 max at WOT to 4500. The other problem I incurred was having a surging effect at 3200 RPM's. The boat hesitate as if it was fuel starved and you'd have to back off RPM's to allow it to catch up. Long story short....it was a CD which was the problem. Changed the CD ....problem resolved...if the CD doesn't solve the problem check the coils.

 

[mreinsmith]

Re: Head Rebuilt - What Next?

Thanks stoops

All the info I found recomended the following prop (which I bought because the old one was damaged). This was the "middle of the road" prop of the 3 the book recommends.

Michigan Match Aluminum
3 Blade
13.25" dia x 17" pitch SR

Does that look right?

Havn't had a chance to work on it in the last week, but I want to go over the electrical.

Thanks again

M