re riggin the 2800sx....

[demag67]

iunfortunately because of the one year difference and the 1 power head still has 1 2Piece cylinder head on it it's going to run a little hotter. it was the same way with me with the 1 power head without the poppet valve. when are you planning on water testing it

 

[2tonchevy]

iunfortunately because of the one year difference and the 1 power head still has 1 2Piece cylinder head on it it's going to run a little hotter. it was the same way with me with the 1 power head without the poppet valve. when are you planning on water testing it

hey man!

i actually got a head gasket and changed out the heads prior to installing the power heads and now all the heads are one piece. and the one that ran hotter was the one with the red flywheel (the one with the line running from the popet housing to the top of the block.) is that the one that ran hotter with you as well???? the good thing is at least i know the thermostats are doin their job....they opened like clockwork every time at about 150 deg cylinder head temp.

the other engine didnt get as hot (maybe 120-125) and the thermostats didnt seem to open. the difference in behavior made me a little concerned....was kinda expecting them to work in the same way and have similar heat numbers.....

i found a several small water/fuel lines that needed to be cut and re attached. just worn and leaking pretty good so i cut em and re installed and put zip ties on em.


so i guess everything looks to be a go...hope to get a test in this weekend but the weather isnt lookin too great. we'll see.

the boat is finished, cleaned out, washed, and ready to go. i love this boat.

 

[demag67]

I can't remember which one was hotter, but one was just slightly hotter. that's why I put new thermostats in them. they were like that since I owned them. they would never overheat so I just left them alone.

 

[2tonchevy]

I can't remember which one was hotter, but one was just slightly hotter. that's why I put new thermostats in them. they were like that since I owned them. they would never overheat so I just left them alone.

ok cool!

i got em all buttoned up and ready to go. just gotta find some nice weather to do some testing.

 

[JUPITER PULSARE]

Just thought I'd give you guys and update for Max. He's got his 28 rigged with the twin 2.4's, ran it the other day with some minor overheat issues on one motor. Installed a new impellor today and is heading to the water! Looking forward to hearing some good news!

 

[2tonchevy]

thanks for the update Steve!

i went out for another round yesterday and no luck.....starboard motor still run up to 180 in about 30-45 seconds after planing and the hot horn starts goin off. the port seems to do fine but in all honesty i havnt been able to run it at speed long enough to make a good judgement......they will idle all day and the tell tale stream looks strong. removed popet valve yesterday to inspect and it looks fine to me (this engine as the hose running from the top of the motor to the popet) so i just got some new gaskets and will re install today. its acting like the popet valve isnt opening. as soon as i bring it back off plane it cools back down to bout 145 degrees. (im using the stock cylinder head temp units)

i havnt ruled out the possibility of the engines being too high......but they seem to plane out and hook up great where they are now....

im seeing 9-10psi pressure at 3500-4000rpm cruising. i havnt been able to play with the trim or get any kind of speed numbers but it turns the 26 hydromotives easily and has no problem planing out even with a full tank of fuel, 600 pounds of passengers and full gear. i pushed it up to 6000 rpm and could have went higher before the buzzer went off anf i had to back down,


any ideas on how i can test some htings to diagnose the problem without just guessing?? i have heard of some people removing the popet valve, removing thermostats, etc......

 

[2tonchevy]

question:

is there supposed to be a constant flow from the tell tale (thermostat dump at all times? even when first started? as soon as i fire the motor up the tell tale stream is wide open.....

question:

i read on scream and fly that alot of guys have fixed similar overheating problems by replacing the thermostats with fender washers allowing more constant (yet restricted) flow through the heads....

ive also read where some guys remove the popet valve alll together.....and have had success....(Eagleone does this and hes been racing and building engines for 40 years...)

just lookin for some things to try....im kinda outa ideas at this point...

 

[Jimway]

Give some thought to the exhaust manifold seal and gasket.

 

[mateman]

My 87 200 would do the same thing. I replaced both thermostats and the popet valve with new ones. This solved the problem for me. Good luck and cant wait to see this one running again.

 

[2tonchevy]

thanks for the advice guys!

Jimway: what and where exactly is the exhaust manifold gasket and seal???? (forgive my ignorance here but im not familiar with the terminology) i just replaced the seal / gaskets between the two piece plates last year and they have less than 10 hours of run time on them since. the powerhead base gaskets are also new.....what about the exhaust chest gasket in the middle.....it seems some people have had issues with them causing similar problems.

im gonna pull the thermostats today and see what i see....i may try running the stainless fender washers everybody seems to be running.

i hope my motors arent too high cus it seems to perform great just like it is.....

 

[demag67]

Max, its got to be something stupid. Maybe the spring in the poppet valve or maybe one of the thermostat s isn't opening or is stuck open or something. Did you check with a temp gun on both heads.

 

[Jimway]

Yes, what you term the exhaust chest gasket. Keep in mind that a 'gasket' might be in place but still not 'seal'. Look at water passage diagram to study flow direction and design operation. If the pump,stats, pop valve, flow and pressure, is all ok, perhaps some leakage from the exhaust system passages is finding it's way to the cooling passages? That's what I was thinking about.

 

[2tonchevy]

Yes, what you term the exhaust chest gasket. Keep in mind that a 'gasket' might be in place but still not 'seal'. Look at water passage diagram to study flow direction and design operation. If the pump,stats, pop valve, flow and pressure, is all ok, perhaps some leakage from the exhaust system passages is finding it's way to the cooling passages? That's what I was thinking about.

ok i gotcha....

i will def check everything out.

gonna put new stats in just to eliminate possibilities. took the poppet valve apart and lubed it with wd40 and inspected it.....looks ok to me....gnna try and run it with new stats and poppet re installed this week. if it doesnt do right i am going to try and run the fender washers and no poppet like Eagleone on scream and fly suggested. seems to be alot of people eliminating cooling issues by doing this....sometimes takes a lil tweekin to get it just right but once diale din seems to be pretty fool proof.


like i said.....my motors could just be too high......but man it planes out and runs/ rides so good.....even with three adults, full gear, two coolers and 90 gallons of fuel.....id like to run the engines as high as i can....

it will spin the 26 hydromotives up to 6000rpm easily....

 

[demag67]

max, replace the spring and the poppet valve. I replaced the valve and seal along time ago but maybe it is bad again. if you can try the washers or make sure the thermostats are 120 degree stats.

 

[demag67]

max, I think I gave you a exhaust chest gasket. if so pull the plate on the back, and take a look in there like jimway said.

 

[2tonchevy]

max, I think I gave you a exhaust chest gasket. if so pull the plate on the back, and take a look in there like jimway said.

man thats right you did!

i will def check that out before running again. i will also be ordering new stats and a poppet valve hit from pro marine today.

the stats that came out of that motor are 143 degree stats....the poppet valve looked great to me...no visible wear at all.

 

[2tonchevy]

ordered thermostats, exhaust divider gaskets, poppet kits, and head gaskets for both motors. gonna give em a good looking over and replace said items. also gonna pull the lower and check the placement of the copper tube (some guys have said if they get pushed up in the exhaust plate they will do what i am experiencing.

talked to Ricky at pro marine and he said its very possible my engines are too high....

 

[SCT]

2ton, are you running low water pick ups? If not, did you block off the top inlets....could be sucking air.

 

[2tonchevy]

2ton, are you running low water pick ups? If not, did you block off the top inlets....could be sucking air.

sct - yes i have bob nosecone with lo water pickups,


it seems like the props would blow out and i would have trouble gettin on plane if the engines were too high. the boat planes great.....the prop shafts are 2 inches above the bottom in front of each bullet and the bullet is 26 inches from the transom. (they are acually farther than that from the bottom of the boat since the bottom of the transom is notched on the 2800sx,,,,)

 

[SCT]

I agree, plus you would have problems on both engines if they were to high. What psi are they running?