auto choke-cold start prob 90 hp yamaha

[hogfish1]

Alot of boaters in my area have the same cold start problem I have. First start of the day difficult if not impossible unless engine is run every week. All normal start procedures ie bulb priming, throttle not off idle position,performed as per operators manual. All starts after warm up are instantaeous. My last 90 yamaha with manual choke never problematic. This 2000 model ify since new.Anyone else having this difficulty? Anyone heard of a cure?

 

[pine island fred]

Re: auto choke-cold start prob 90 hp yamaha

Is this a 2 stroke or 4 ? had a 4 stroke f-80 with same problem. regards fred

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

Thanks for the reply Fred. It's a two stroke. Similar postings appear in the archives for other engines, but I suspect that the wax bulb enrichment circuit in this 90 hp two stroke is a whole different animal than the four stoke engines. Before I R&R the carbs, check float level,etc. I was hoping that someone had an even more basic starting point to resolve this incredibly frustrating condition. I still have my old 90 Yammie and I am tempted to look into retrofitting the old carbs and choke system onto the newer motor.

 

[msd58]

Re: auto choke-cold start prob 90 hp yamaha

I have the same problem. 1997 Yamaha C90 Cold start is really tough sometimes. I live in the northeast too

 

[bigbrownbuku]

Re: auto choke-cold start prob 90 hp yamaha

try using the manual function lever on the electric choke at startup. if that helps get your choke checked for correct operation.

 

[msd58]

Re: auto choke-cold start prob 90 hp yamaha

OK, But do you find the manual choke lever?

 

[Ray Neudecker]

Re: auto choke-cold start prob 90 hp yamaha

It is on the front of the engine cowling.

 

[msd58]

Re: auto choke-cold start prob 90 hp yamaha

I have a 1997 model. Is it in the same location on all?

 

[bigbrownbuku]

Re: auto choke-cold start prob 90 hp yamaha

its a little red lever located on the electric choke. there should be a corresponding decal to tell you the correct orientation. take the cowl off and look in the area of the carburettors.

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

Verifying the repair beyond a doubt in cold and windy weather is difficult but I think I resolved my hard start! Because of concerns about contamination reaching the carbs, I installed a 40 micron in line fuel filter and on a whim decided to replace the adjacent bulb that you pump on start up ($16.00 for both). I suspect that the check valves in the old bulb allowed the carbs to drain back to the tank after a few days of sitting. The new bulb becomes completley turgid within one or two pumps - no remarks please!!- where the old one remained very slightly mushy. The degree of mushyness did not raise the suspicions of the dealership technicians on two previous repair attempts so I guess I should'nt feel too bad about my diagnostic abilities. Back to basics and start with the easiest and cheapest first. Hope this helps others that may have the same problem. I suffered with it for 2 years.

 

[msd58]

Re: auto choke-cold start prob 90 hp yamaha

How old was the priming pump bulb?

 

[seahorse5]

Re: auto choke-cold start prob 90 hp yamaha

Common problems with that Yamaha Prime Start system are fuel deposits in the primer section that sometimes also cause the plunger needle to stick and the wax element itself.<br /><br />Sometimes you can get it working better by removing the plunger assembly and putting it in the freezer for several hours. Measure the length of the plunger, then hook it up to a 12 volt battery and watch the plunger extend as the wax heats up inside. Let it cool, then re-install in the motor.

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

msd58.... I thought the bulb was replaced along with the fuel hose when the fibreglass fuel tank delaminated and trashed the fuel system in 2002 but at this point I can't be certain. I had an R&R and D&A on the carbs. tank replacment and fuel hose exchanged at that time. As an aside.. Pate makes a fine fuel tank for the Boston Whaler but the life expectancy is 10 years and I can tell you from experience you don't want to wait until it comes apart internally to replace it. No leaks - just gunk that trashes the fuel system and if that trash reaches a high speed jet you'll burn a piston. I was lucky.

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

seahorse.... Great input! I was hoping that someone that had familiarity with this system would post. I've had the carbs off and cleaned them with compressed air, Inspected float needles and seats etc. and I like the idea of working the plunger assembly as you described. I did have one question though... If I recall correctly, the enrichment module was on the center carb. How does it influence the upper and lower carb mixtures? Does the system just enrich the center one and count on diffusion within the crankcase to even things out?

 

[seahorse5]

Re: auto choke-cold start prob 90 hp yamaha

You will see a gray hose that comes out of the area by the plunger. It goes into the intake manifold by #1 carb and there are machined passageways that will allow the fuel to flow to all 3 reed blocks.

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

Much appreciated Seahorse. That info filled the knowledge gap. Bulb replacment has seemed to be the remedy in my case so far. I thank you for the professional insight.

 

[msd58]

Re: auto choke-cold start prob 90 hp yamaha

hogfish we have the same set up:<br /><br /> http://image18.webshots.com/18/8/45/17/216084517XamWgu_ph.jpg

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

msd58... Sweet! Nearly identical to my '85 Montauk. Best boat I've ever owned. Ours has been in the family since new and I have no desire to "upgrade" to bigger, faster and higher operating costs. If the group will forgive an off topic question, was the dive platform installation a bear?

 

[msd58]

Re: auto choke-cold start prob 90 hp yamaha

I don't have a swim step on my boat. I think what you see it a piece of rope that looks like the handle on a swim step. They look easy to put on. Try:<br /> http://continuouswave.com/cgi-bin/Ultimate.cgi?action=intro <br /><br />For more info

 

[hogfish1]

Re: auto choke-cold start prob 90 hp yamaha

My mistake. I've seen the posts on continuouswave...great site. The wood diagram shows a small block on either side of the wood in the center of the transom where the motor mounts but the odd contour of the transom and general lack of wood in the area requires most owners to either spread the mounting stress over a larger area with oversized fender style washers on the inside of the hull or to insert additional wood discs inside the foam sandwich parts of the transom. I guess I'll either keep climbing onboard using the engine as a ladder or look into the removable center post ladder that clips on to the transom.<br />Thanks to all for the responses.