mikuni fuel pump on my vro 110hp rude

I installed a $58 mikuni snowmobile diaphragm fuel pump today and the engine in the test tank sounded good. I have an 86 110hp rude with a bad non vro fuel pump. To replace it was over $400. I will test it out on the water under full load as soon as I get chance.

Re: mikuni fuel pump on my vro 110hp rude

Cool. Looks like a good vacuum type pump. Which model # are you using?

Re: mikuni fuel pump on my vro 110hp rude

It's part# df62-702. I was able to mount it to the bubble back housing by cutting a slot on 1 mounting hole on the pump. There are 2 threaded holes that worked perfectly. I cut and soldered brass barb connections to connect the 1/4" lines to my motor's 5/16" lines. I still have to test in the water under full load. I ran it in a large test tank with the prop on and it shot out the water in seconds.

Re: mikuni fuel pump on my vro 110hp rude

I hope it works out for you. However, 1/4" fuel lines are pretty small. The V-4's required 3/8".

I fear you may starve it for fuel at full throttle/full load. If you do, you will melt it down quickly, with no warning.

Re: mikuni fuel pump on my vro 110hp rude

if you could get one of those pumps with 5/16 barbs it would be cool. I have been looking for a good fuel pump alternative for the over priced/poor quality VRO pumps.

Re: mikuni fuel pump on my vro 110hp rude

SparkieBoat said:

over priced/poor quality VRO pumps.

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I disagree. They aren't cheap but they are complicated and provide a no hassle alternative to mixing fuel/oil.

The oil pumps have been blamed FALSELY for everything from global warming to toothaches. They rarely fail due to mechanical breakdown. Hardly anyone ever services the oil injection system (tank/lines, etc.) so they fail to be able to pump oil.

I have to laugh when someone blames the system for the melt down of one piston/cylinder. The system IS NOT cylinder selective. It injects oil BEFORE the carburetors.

Re: mikuni fuel pump on my vro 110hp rude

yea most cylinder melt downs are from dirty cards or lean condition. But I cannot see $400 as a reasonable price for those fuel pumps. The ones from the 90s really sux bad and have a very high rate of failure, mostly on the fuel side though not the oil side. I am a pre mix man anyway and could care less about the oil side,(there have been instances where alarms failed and engines got ruined by oil failure) but even the pump with no oil side is $400, completely ridiculous price. It can be replaced by using the older style 2 pump system, but then you have to build your own brackets and rig some stuff, even then you get over $200. Even the rebuild kits for the VRO pumps are over $100..I mean really $120 for some seals and a diaphragm...I just hate it when a manufacturer has you bent over the barrel and sticks it to you every chance they get. kinda pisses me off and makes me look for viable alternatives. Thank God for the various aftermarket guys who keep many of the parts cost in check. For whatever reason no one has produced an aftermarket VRO pump that i know of anyway.

Re: mikuni fuel pump on my vro 110hp rude

SparkieBoat said:

yea most cylinder melt downs are from dirty cards or lean condition. But I cannot see $400 as a reasonable price for those fuel pumps. The ones from the 90s really sux bad and have a very high rate of failure, mostly on the fuel side though not the oil side. I am a pre mix man anyway and could care less about the oil side,(there have been instances where alarms failed and engines got ruined by oil failure) but even the pump with no oil side is $400, completely ridiculous price. It can be replaced by using the older style 2 pump system, but then you have to build your own brackets and rig some stuff, even then you get over $200. Even the rebuild kits for the VRO pumps are over $100..I mean really $120 for some seals and a diaphragm...I just hate it when a manufacturer has you bent over the barrel and sticks it to you every chance they get. kinda pisses me off and makes me look for viable alternatives. Thank God for the various aftermarket guys who keep many of the parts cost in check. For whatever reason no one has produced an aftermarket VRO pump that i know of anyway.

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I just don't think a snowmobile fuel pump is capable of delivering the volume of fuel needed by a 100 c.i.d. (99.6) outboard at load or W.O.T. The 1/4" fittings are awfully small.

However, we'll find out. I hope I'm wrong. Hopefully, not at the expense of a perfectly good engine.

Re: mikuni fuel pump on my vro 110hp rude

I agree..just the fact that it has 1/4 fittings would make me not do it. But it would be nice to find an under $100 alternative that would work without much modification.

Re: mikuni fuel pump on my vro 110hp rude

SparkieBoat said:

I agree..just the fact that it has 1/4 fittings would make me not do it. But it would be nice to find an under $100 alternative that would work without much modification.

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There are alternatives. NON oil injection fuel pumps can be adapted. Those would be from the SPL line (88, 112) of the same/similar year.

Re: mikuni fuel pump on my vro 110hp rude

yea thats true for the V-4..i mostly deal with V-6 engines..I do not think the v-4 pump would work..would it??

Re: mikuni fuel pump on my vro 110hp rude

SparkieBoat said:

yea thats true for the V-4..i mostly deal with V-6 engines..I do not think the v-4 pump would work..would it??

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Based on past knowledge. For a V-6- you would need TWO.

Re: mikuni fuel pump on my vro 110hp rude

that is what i thought...thanks for your input...dsujen should order the fuel pump for the 112 special and not use the mikuni one that he mentioned..I priced them at under $70

Re: mikuni fuel pump on my vro 110hp rude

The stock fuel pump on my 110 only has 1 5/16 fuel line going to a plastic manifold that connects both carbs together. The mikuni pump is rated for 65 liters per hour which is more than what is required for this engine. The pump has 2) 1/4 inch outlets to go to the carbs which is bigger than what it had because I am using both outlets. If I mix my fuel and the pump isn't enough for wot how can this melt down the cylinders? It will just not have enough power. All the pump does is keep the bowls filled. It doesn't change the fuel/oil mix or create a lean condition.

Re: mikuni fuel pump on my vro 110hp rude

a lean condition is created when you have too little fuel or too much air..i forget the exact ratio, but basically if you have too much air from lack of fuel flow it will cause the cylinder(s) to burn at too high of temperature resulting in burning a hole on the piston. it may work fine. But if it were my motor I would put the fuel pump from the 112 special on it. it cost about the same price. the mikuni pump does not mix the oil does it?? you are premixing I assume.