Shaking really bad once warmed up

[pstephens46]

I am not clear, as usual. No alarm sounded? Correct?

The shaking certainly got the OP's attention. If indeed he has an overheat the system worked well as a secondary alarm.

Stick shaker Panasonic!

[panasonic]

I am not clear, as usual. No alarm sounded? Correct?

The shaking certainly got the OP's attention. If indeed he has an overheat the system worked well as a secondary alarm.

Stick shaker Panasonic!

He never said anything about any alarms....just shaking. Should be an alarm, unless it not working, or not installed.

When holding on to a tiller handle engine and RPM reduction kicks in....feeling like its missing very badly...and shakes a lot.

Stick shaker in aircraft will wake up the dead...and when that starts going off you probably are going to have a bad day or already having a bad day.

[Miraclegrow]

Just got finished rebuilding the water pump will do a test drive in the morning. The old impeller was missing the key I would assume that Had alot to do with it over heating.

[TownsendsFJR1300]

Just got finished rebuilding the water pump will do a test drive in the morning. The old impeller was missing the key I would assume that Had alot to do with it over heating.

Yep, it might...

That's exactly why I posted to check basic stuff FIRST.

Gentlemans bet your good to go?

[99yam40]

my question is where did the key go?
hard for it to just disapear

[panasonic]

I bet he will be go to go now.

[TownsendsFJR1300]

my question is where did the key go?
hard for it to just disapear

Even if it sheared off, part would still be in the drive shaft.

I see no other way except it WASN'T re-installed (last service)..

[pstephens46]

Or it was baby tapped into place. I got one seated a little crooked one time. Forced the impeller slightly out of round. Distorted maybe a better term. You could feel it when you rotated driveshaft by hand.

[Miraclegrow]

Well that fixed it, ty everyone for the help. I looked everywhere couldn't find the key

[zenoahphobic]

I would not rule out that the engine has suffered some damage, as the shaking seemed to be attributed to overheating and not from shutdown mode, this could only come from it starting to seize up. The pistons would have jammed in the cylinder(s) possibly causing scoring and damaging the rings.
On the issue of the water pump, additional flow can be achieved by having a takeoff within the jet container - like a JetSki does.

[TownsendsFJR1300]

On the issue of the water pump, additional flow can be achieved by having a takeoff within the jet container - like a JetSki does.

Huh? Please splane..

[99yam40]

Huh? Please splane..

I would think when the jet is running there could be additional water from that to run up to the power head

[zenoahphobic]

I would think when the jet is running there could be additional water from that to run up to the power head

Precisely, behind the propeller (impeller) there is substantial pressure in the jet pump housing. A simple nipple or pitot tube is passed through the housing with a tube attached outside going up into the engine cooling system. As there is no neutral selection the impeller is rotating all the time the engine is running.
Not having looked at an outboard jet attachment, I assume the situation is the same. Therefore when engine is running there is water pressure available. So I wonder whether the OP's standard water pump was not needed as there was a simpler and more efficient water available from the jet housing?
You would need to remove the attachment to see if there is a connection to the water inlet, passing through or bypassing the existing outboard water pump. If so that might have needed checking.
Might explain the "spinning" impeller?

[TownsendsFJR1300]

Looking at the parts diagrams, there doesn't appear to be any additional water flow and it does have a "standard style" water pump impeller:

The main propullsion impeller and housing does NOT show any additional water flow to the power
head.

WP:
http://www.boats.net/parts/search/Ya...F90/parts.html


http://www.boats.net/parts/search/Ya...F90/parts.html

http://www.boats.net/parts/search/Ya...F90/parts.html

2006 and Later F90TJR Y-8900010 Yamaha Jet Drive MAIN HOUSING F90 Diagram and Parts


.

[zenoahphobic]

[QUOTE=TownsendsFJR1300;146563]Looking at the parts diagrams, there doesn't appear to be any additional water flow and it does have a "standard style" water pump impeller:

The main propullsion impeller and housing does NOT show any additional water flow to the power
head.

WP:
2006 and Later F90TJR Y-8900010 Yamaha Jet Drive WATER PUMP ADAPTER F90 Diagram and Parts


2006 and Later F90TJR Y-8900010 Yamaha Jet Drive DRIVE 1 F90 Diagram and Parts

2006 and Later F90TJR Y-8900010 Yamaha Jet Drive INTAKE ASSEMBLY F90 Diagram and Parts

2006 and Later F90TJR Y-8900010 Yamaha Jet Drive MAIN HOUSING F90 Diagram and Parts

Thanks for the diagrams.

It's a pity that the engineers of this jet drive did not have the foresight that their counterpart JetSki engineers did. They prefered to stick with the standard, multi parts, additional maintenance prone water pump system. Their jet ski cooling just has a gland fitting with a tube attached - no moving parts, no maintenance required and far less cost.
I wonder if "No.31 flush screw" was an attempt at doing this but the lunch whistle got in the way. (Can't see that being a flushing inlet when one can simply shove up a hose to flush the unit).
The only reason I can see by keeping the "proven pump" design ( but I don't think it justified), is that the casing casting would have to be more complicated to include the water passage internally, to keep the inside and outside of the jet unit streamlined.