Going back to oil injection 951

[Noahsfixingbrokedownskis]

I just bought two 1998 seadoo 951s gsx's; one is the gray ghost with white engine and one is the red traditional normal unit with the silver engine. Both had been converted to premix by previous owner. I've owned skis before that have been on premix and I wasn't really a fan as they burn a lot more oil than when using the oil injection and full synthetic oil is not cheap. The previous owner left the oil pumps on the units and simply capped them off when they did the conversion. My question is if I convert these back to oil injection should I buy two new oil pumps as the pumps would have been running dry with no oil for an undisclosed amount of time. I'm assuming leaving the old oil pumps on the ski, but having no oil hooked up to them could possibly ruin the oil pumps or at least decrease their life. The other question is, is it really worth going back to oil injection or should I just leave them on premix. The engine on the gray ghost was only at 110 for the compression so I'm having that one fully rebuilt including the crank and already have that engine pulled from the ski. The Red ski more than likely has been rebuilt in the past because the compression was at 125 which is a little low but still runnable. I paid 1400 for the 2 skis and a double trailer and I'm looking forward to working on them this winter.

 

[etemplet]

Oil Injection is more convenient. On the pumps, did they only cap the oil or did they remove the pump drives? I'd surely replace the pumps if they ran them with no oil but you can test them. I would expect them to seize up but... one never knows.

Even with injection I run 100:1 premix. I like a little oil in the mix. It also stabilized the fuel and provides extra oil at low RPM. My preference. I find premix a pain in the but if you are riding a lot, carrying fuel containers, premixing.... remembering which containers have premix.... LOL thank goodness for the color. Injection is one less thing to worry about. I bet those skis FLY with 951s in there. Good luck !!

 

[Noahsfixingbrokedownskis]

Oil Injection is more convenient. On the pumps, did they only cap the oil or did they remove the pump drives? I'd surely replace the pumps if they ran them with no oil but you can test them. I would expect them to seize up but... one never knows.

Even with injection I run 100:1 premix. I like a little oil in the mix. It also stabilized the fuel and provides extra oil at low RPM. My preference. I find premix a pain in the but if you are riding a lot, carrying fuel containers, premixing.... remembering which containers have premix.... LOL thank goodness for the color. Injection is one less thing to worry about. I bet those skis FLY with 951s in there. Good luck !!

The previous owner simply disconnected and capped the oil line that runs to the injector pump. There was literally no oil running to the injector pump that was left connected and it was also left spinning as the engine magneto still had the plastic oil pump engagement piece connected. So I may buy some used injector pumps off of eBay just for peace of mind when I put them back together.

 

[etemplet]

The previous owner simply disconnected and capped the oil line that runs to the injector pump. There was literally no oil running to the injector pump that was left connected and it was also left spinning as the engine magneto still had the plastic oil pump engagement piece connected. So I may buy some used injector pumps off of eBay just for peace of mind when I put them back together.

You may be able to test them just out of curiosity. You're probably looking at $50 each for the pumps used,

 

[Noahsfixingbrokedownskis]

If I stay premixed, on the 951 other than removing the oil pump, installing a block off and running 40:1 full synthetic. I can totally remove the oil tank? No oil lines run to the engine on the 951?

 

[burtshaver2021]

If I stay premixed, on the 951 other than removing the oil pump, installing a block off and running 40:1 full synthetic. I can totally remove the oil tank? No oil lines run to the engine on the 951?

That’s correct

 

[etemplet]

A lot of old school 2-stroke motorcycle and outboard guys won't run injection pumps. A lot of engines failed because of pumps or the associated systems. That carried over to today as old wives tales. I think back then there were many more mechanical people that worked on their own stuff. Today not so much. Few people today have reasons to ditch the oil injection system especially when you are lugging around 3 5-gallon cans on pre-mix. LOL

 

[Venturian1]

When I was considering going to Pre-mix, I contacted BRP or Rotax via email, asking for the exact ratio and type of oil I should run, the reply was it depends on your engine, and year, then after providing that info, were still reluctant to be specific, and it boiled down to them saying these oil injection pumps are variable rate, meaning, at idle, the engine is running less oil than WOT. Example given was it could be idling at 100:1, but at WOT, the injection rate could be 20:1. So I decided to not mess with it, and dismissed all of the scary things I read about injection pump failure, and have had no issues yet. Now I do own a pair of waverunners, ( 97 1100 3 cyl, & 97 760 w/aprox 105 hrs on both, and they had black sludge at the bottoms of the tanks that only acetone would dissolve, both last registered in 2003) and after getting going, smoked like a freight train at idle. I found there was no adjustment to calibrate, no throttle cable run to the injection pumps, instead, they have a fixed rate of injection per crankshaft revolution, so as the rpms increase, so does the oil. Noah is right about the engine consuming more inj oil when using pre-mix, a lot more! I was buying a gallon a week, and then all the extra work of measuring, hauling gas cans, pouring, etc. I've got these Yamahas up for sale, cheap, even though they are faster.

 

[tobytd]

Beware of white engine problems.
Lean jetted carburetors…
Etc. etc.