OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

[apollothesun]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Thank you for your reply but this is not mounted to a lower unit, it is mounted to a jet drive which does not have an impeller. The jet drive is designed to take in water for coolant which is why there is no real gearing, direct drive.. the prop always spins even in "neutral".

I haven't done compressed air. I have flushed it with the water kit and water makes it all the way through the engine and out the back pee holes but it just doesn't build up enough pressure to fill up the engine completely and cool it efficiently.

oh, i see,jet drive. bump for ya, hopefully someone knowledgeable with a jet drive can help ya out

 

[troybuz]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Tmfeaster,
I too have an OMC Turbojet, and seem to be struggling with some of the same issues of running hot, water pressure, no tachometer, etc. I have a brand new powerhead and am trying not to scorch her while I figure things out.
If you don't mind, Email me and maybe we can chat troybuz@comcast.net
Thanks,
Troy

 

[tmfeaster]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Troy,

Sorry I haven't had much time to respond, I have been working like crazy and not on the boat sadly enough.

I will get back to you as soon as I can. At this point I am going to have to start testing all hoses and fittings where water goes through because the engine passages are clean.

 

[troybuz]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

tmfeaster,
Not sure if I mentioned a water flow issue I solved, but my intake water supply line was squished flat between the engine housing and the jet pump, so I was only getting a trickle of water. Since that fix, my temps are very good.
Troy

 

[tmfeaster]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

tmfeaster,
Not sure if I mentioned a water flow issue I solved, but my intake water supply line was squished flat between the engine housing and the jet pump, so I was only getting a trickle of water. Since that fix, my temps are very good.
Troy

I have traced all hoses and connections, all are good. Still can't figure out how I am losing water pressure and not staying cool.

I know water makes it all the way through the system as it does come out of the back exit water holes, just slowly. If I plug up the smallest exit water hole it builds up water pressure but of couse gets hot quickly since the hot water is not exiting the engine. I can't find anymore leaks, I am lost!

 

[BinzlBrew]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Hi,

I too have been racking my brain trying to figure out why I overheat. Port side temps are great(135) but starboard side overheats. Is water pressure suppose to stay at 20psi? I replaced thermostat and now no water out of pee hole.

 

[86 century]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

over heating on omc 115 turbojets is most of the time caused by junk geting in the bypass check ball in the pump.

Mine overheated once I pulled the t stats and popits on the eng(left them off)then clean the ball and stretch the spring out stuffer back in runns nice and cool.

 

[BinzlBrew]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

I attempted to take that ball bearing regulator out yesterday and in will not budge. I stripped the screw to top it off. I tried everything and it will not move. I think I'm gonna have to drillit out. I already have the replacement screw. I hope it works.

 

[BinzlBrew]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

All ideas and/or suggestions are appreciated

 

[troybuz]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

BinzlBrew, I will try to explain my water supply system, which might work well for you.
First off, you are having the same issues many have had...a plugged supply orifice in the pressure valve area, and it sounds like you cannot remove the screw thus no able to service the unit.
My solution was to drill and weld a 1" nipple off the nozzle...this now becomes a second supply line (redundant water, and lots of it). I run both water supply lines into a KEM Sand Filter (in place of the screen strainer).
To regulate water pressure I installed a 20 PSI pressure reduction valve, so any over pressure water is expelled, thus not over pressuring the block. I also added a water pressure gauge off the bubble back (mine was drilled for this, some are not) to monitor water pressure.
Now, I have excellent water supply, excellent water filtration, and pressure control. Plus my heads now run about 150- 160, which is perfect.
Also, please be careful removing the thermostats. Yes, it will run, and run cold...and that's not good. My last motor suffered a cold water seizure from running the heads too cold! That cost me a $3,000.00 power head; Ouch!
I have pictures I can send you if you're interested.
Good Luck,
Troy

 

[86 century]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

I ran mine most of the summer with no stats.

I have had no problems with it running to cold these things have flow problems as it is.
A cold water seizure afraid I dont understand.

 

[toddschubert]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Sorry if this point has been touched on already as I did not read all post.
But that engine has water deflectors under the heads and if flattened by heat and preassure (sposed to be round) will definately cause overheat problems

 

[toddschubert]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

And yes...keep therms in place. OK to run test with but long term use w/o not good idea. When testing mine stb bank(1&3) ran 30 deg warmer than 2&4 and this alone can't be good.

 

[BinzlBrew]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Is there any sure-fire way of drilling or tapping that screw out without damaging the existing threads?

 

[toddschubert]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Would loosenin and dropping the lower cover buy you anything? I do that to take off thermostat housing

 

[25xs]

Re: OMC "Primer" cold start system operation

Re: OMC "Primer" cold start system operation

I just caught this thread and thought I would say a little about what I have read here...

[This does not apply to the RARE electric fuel pump applications, because the electric pump runs as soon as you turn the key] The "push to choke" feature of OMC/BRP engines having a little black solenoid with a red lever under the cowling doesn't do ANYTHING unless there is fuel pressure (e.g. someone holding the fuel line primer bulb tight, OR the engine is cranking/running so the fuel pump is working).

Turning the key one click then holding in for several seconds just puts several seconds of time on the primer solenoid... Only a tiny spurt of gas will flow before the fuel pressure is relieved, not usually enough to start it more than a brief pop. [Again, the electric fuel pump applications are the exception.]

A guaranteed cold start on most all OMC engines is to hold pressure on the fuel line primer bulb while someone else (or you) turn the key one click and push in for a few seconds... Then when you crank it, the engine has just received a few seconds' squirt of raw gas and should pop right off. You can continue holding in on the key switch after it's started and release it as long as the engine will keep running. Holding it in longer for cold starts or cold weather starts.

The TurboJet pump unit is NLA (no longer available) and no longer manufactured by the original company (TurboJet made it, not OMC). A problem is pump impeller cavitation (explains the performance issues of this original post) and the air intrusion created in the cooling water possible when the pump cavitates. The cooling water line simply taps into the pump housing behind the impeller where the water is high pressure... Cool, since no traditional rubber blade waterpump impeller is required. This is how all the PWC's get their cooling water as well and overheating them is certainly a very rare occurance as far as engine failures are concerned.

A couple years ago, there was one complete TurboJet drive and a few parts left in the manufacturer's inventory and they weren't much interested in helping with any questions...

There ARE, however, tons of TurboJet parts & information available via google & ebay searches. Also literally TONS of the Regal "Rush", FourWinns "Fling", Baja "Blast", Sunbird "Sizzler", etc... They all offered some version of jet boat in the early 1990's...

 

[toddschubert]

Re: OMC Crossflow v4 115hp Turbojet - Overheated/Ignition and Head Problems

Bumping the key and activating primer is also a good cold start proceedure overlooked by some. Just as she starts to die give a little push. Mine takes 2-3 and it's on!